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In This Post we are  providing  CHAPTER 5 SENSORY, ATTENTIONAL AND PEROECTUAL PROCESSESSNCERT MOST IMPORTANT QUESTION for Class 11 PSYCHOLOGY which will be beneficial for students. These solutions are updated according to 2021-22 syllabus. These   can be really helpful in the preparation of Board exams and will provide you with a brief knowledge of the chapter.

NCERT MOST IMPORTANT QUESTION ON SENSORY, ATTENTIONAL AND PEROECTUAL PROCESSESS

Question 1:

Explain the functional limitations of sense organs.

ANSWER:

The functional limitations of sense organs of human beings refer to their limited range of stimulation. In order to be noticed, a stimulus has to be of an optimal intensity and magnitude. Thus, the stimulus has to carry a minimum value or weight. For example, our ears cannot hear very faint or loud sounds. Similarly, our eyes cannot see objects in very dim or very bright light.

Question 2:

What is meant by light and dark adaptation? How do they take place?

ANSWER:

Light adaptation is the process of adjusting to bright light after exposure to dim light. This process often takes a minute or two to be completed. Dark adaptation, on the other hand, refers to the process of adjusting to dim light after exposure to bright light. It may take half an hour or longer depending upon the level of exposure.

Light and dark adaptation takes place due to photochemical processes. Light adaptation takes place when the molecules of rhodopsin or visual purple in the rods of the eye get bleached or broken down, as a result of the action of light. Dark adaptation takes place when the light is removed allowing for restorative processes that regenerate the pigment in the rods with the help of vitamin A.

Question 3:

What is colour vision ?

ANSWER:

Colour vision is the ability of the eyes to see and distinguish between colours based upon their varying wavelengths in the visible spectrum of light. The vision of colours depends on the visible spectrum, which includes the range of energy detected by the photoreceptors. Further, the colours are a psychological property of human sensory experience. They are created by the interpretation of the information received by the brain.

Question 4:

How does auditory sensation take place?

ANSWER:

Auditory sensation takes place when sound enters the ear and stimulates the chief organs of hearing. This involves the production of cyclical displacements of molecules in the air. Auditory sensation refers to a subjective hearing of something, and audition is an important sense modality, as it provides spatial information and plays an important role in spoken communication.

Question 5:

Define attention.

ANSWER:

Attention refers to the process through which certain stimuli are selected from a group of others. It requires an allocation of effort. The objects that are at the centre are the focus of attention while objects that are away from the centre are at the fringe.

Question 6:

State the determinants of selective attention. How does selective attention differ from sustained attention?

ANSWER:

The determinants of selective attention are following:

• Motivational factors represent our biological and social needs. Instances of the same are the drivers strictly following all the traffic rules.
• Cognitive factors represent interests, attitude and preparatory set. For instance, an average teenager would be more interested in watching a cricket match than reading a novel.

Selective attention differs from sustained attention as sustained attention is primarily concerned with concentration and refers to the ability to maintain attention on an object for even for long duration. Contrary to this, selective attention is related to the selection of a limited number of stimuli from a larger group of stimuli.

Question 7:

What is the main proposition of Gestalt psychologists with respect to perception of the visual field?

ANSWER:

The main proposition of Gestalt psychologists with respect to perception of the visual field is that humans perceive different stimuli as an organised “whole”, which carries a definite form. According to them, the form of object lies in its whole that is different from the discrete parts. The Gestalt psychologist also believes that human perceive everything in an organised form because of the orientation of cerebral processes towards a pragnanz.

Question 8:

How does perception of space take place?

ANSWER:

Space is perceived in three dimensions. This is because of the ability to transfer a two-dimensional retinal vision into a three dimensional perception. Spatial attributes of objects like size, shape and direction, and the distance between objects also contribute towards the perception of space. While the images of objects projected on the retina are flat and two dimensional, it is possible to perceive them in three dimensions by transferring the two-dimensional retinal vision into a three-dimensional perception.

Question 9:

What are the monocular cues of depth perception? Explain the role of binocular cues in the perception of depth?

ANSWER:

The monocular cues of depth perception induce depth in objects when viewed through a single eye. They are also known as pictorial cues as they are used by artists to induce depth in two dimensional paintings. Important monocular cues are relative size and height, interposition, linear and aerial perspective, light and shade, texture gradient and motion parallax.

The binocular cues of depth perception are provided by both the eyes in three dimensional spaces. Their role in the perception of depth are as follows

Question 10:

Why do illusions occur?

ANSWER:

Illusions occur because of a result of a mismatch between the physical stimuli and its perception by the individual. The mismatch is caused by incorrect interpretation of information received by sensory organs. Illusions are called primitive organisations as they are generated by an external stimulus situation that generates the same kind of experience in all the individuals. Some illusions are universal in nature as they are found in all individuals. They are also known as universal illusions or permanent illusions because they do not change with experience and practice. Contrary to this, illusions that vary in different individuals are known as personal illusions.

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HOMEWORK QUESTIONS

In This Post we are  providing  CHAPTER 6 LEARNING NCERT MOST IMPORTANT QUESTION for Class 11 PSYCHOLOGYwhich will be beneficial for students. These solutions are updated according to 2021-22 syllabus. These   can be really helpful in the preparation of Board exams and will provide you with a brief knowledge of the chapter.

NCERT MOST IMPORTANT QUESTION ON LEARNING

Question 1. What is learning? What are its distinguishing features?
Answer:  The process of learning has certain features:

1. Learning always involves some kinds of experience or practice.
   • Changes due to maturation or growth are not learning.
     e.g.: One learns that if the bell rings in the hostel after sunset, then dinner is ready to be served.
2. Sometimes a single experience can lead to learning.
   e.g.: A child strikes a match stick on the side of a matchbox and gets her/his finger burnt. Such an experience, makes the child learn to be careful in handling the matchbox in future.
   • Before it can be called learning, the change must be relatively permanent, it must last for a fairly long time.
3. Learning must be distinguished from the behavioural changes that are neither permanent nor learnt.
   eg. changes in behaviour due to fatigue, habituation and drugs.
4. Learning is a change in behaviour, for better or worse.
5. Learning follows a sequence.

Question 2. How does classical conditioning demonstrate learning by association?
Answer:

• Classical conditioning is a type of learning in which an organism learns to associate stimulus.
• Conditioning is the simplest form of learning.
• Classical conditioning was first explained in Pavlovs experiments in which a dog was kept on a harness with a tube attached to the dogs jaw on one end, a measuring jar on the other end.
• The dogs was kept hungry in the course of experiments, every time the dogs was
  given food a bell was rung before it, slowly the dog become conditioned to believe that the ringing bell meant that food was coming. .
• So, he began salivating at the sound at the bell.
• The dog continued to salivate even when food was not given after the bell.
• Hence, salivation became a conditioned response to the conditioned stimulus. Various forms of classical conditioning are:

1. Unconditioned stimulus (US): This stimulus consistently evoked a response or is reliably followed by one or it has potential capacity to evoke a natural response. e.g. food.
2. Conditioned stimulus (CS): It is also known as a neutral stimulus because except for an altering or intentional response, the first few times it is presented, it does not evoke a specific response.
   Any stimuli which lacks natural capacity to evoke natural response but developes this capacity with consistent pairing with US. For example bell.
3. Unconditioned Response (UR): The response that reliably follows the unconditioned stimulus is known as the unconditioned response, e.g. Saliva due to food. (iv) Conditioned Response (CR): When presentation of the originally neutral conditioned stimulus evokes a response.
   This response is what is learned in classical conditioning, e.g. Saliva s a response to the bell.

Determinants of classical conditioning: 

1. Time Relations between stimuli: In classical conditioning the first three are called Forward Conditioning Procedures and the forth one is called Backward Conditioning.
   The basic experimental arrangements of these procedures are as follows:
   • Simultaneous Conditioning: When the CS and US are presented together.
     It is effective to acquire CR but requires greater number of trials.
   • Delayed Conditioning: The onset of CS precedes the onset of US. The CS ends before the end of the US. It is most effective way of acquiring CR.
   • Trace Conditioning: The onset and the end of the CS precedes the onset of US with some time gap between the two. It is effective but requires greater number of trials.
   • Backward conditioning: The US precedes the onset of CS. It is least effective way to acquire CR.
2. Type of unconditioned stimuli: The unconditioned stimuli used in studies of classical conditioning are of two types: Appetitive e.g. eating drinking etc. according to researches it is slower and requires greater number of trials
   • Aversive e.g. Noise, bitter taste etc. classical conditioning is established in one, two or three trials so it is more effective.
3. Intensity of conditioned stimuli: This influences the course of both appetitive and aversive classical conditioning. More intense conditioned stimuli are more effective in accelerating the acquisition of conditioned responses, e.g.: The more intense the conditioned stimulus, the fewer are the number of acquisition trials needed for conditioning, ie intense irritating noise is more effective.

Question 3. Define operant conditioning. Discuss the factors that influence the course of operant conditioning.
Answer:  Operant or instrumental conditioning is a form of learning in which behaviour is
learned, maintained or changed through its consequences.
Determinants of operant conditioning :
1. Reinforcers

• A reinforcer is defined as any stimulus or event which increases the probability of the occurrence of a desired response.
• The type – positive or negative, frequency, quality and schedule or reinforcer are determinants of operant conditioning.

1. Type of reinforcement:
   • Positive reinforcement involves stimuli that have pleasant consequences.
     They strengthen and maintain the responses that have caused them to occur.
   • Negative reinforcer involve unpleasant and painful stimuli. Responses that lead organisms to get rid of painful stimuli or avoid and escape from them provide negative reinforcement. Negative reinforcement leads to learning of avoidance and escape responses.
2. Frequency/number of reinforcement and other feature :
   • Frequency of trial on which an organism has been reinforced or rewarded.
   • Amount of reinforcement i.e. how much of reinforcing stimulus (food or water) one receives on each trial.
   •  Quality of reinforcement i.e. to the kind of reinforcer. Bread of inferior
     quality as compared with pieces of cake have different reinforcing value.
3. Schedule of reinforcement:
   • This refers to the arrangement of the delivery of reinforcement during trials.
   • When a desired response is reinforcement every time it occurs we call it continuous reinforcement.
   • When according to schedule responses are sometimes reinforced, sometimes not it is known as partial reinforcement and has been found to produce greater resistance to extinction.
4. Delayed reinforcement:
   • It is found that delay in the delivery of reinforcement leads to poorer level of performance.

Question 4. A good role model is very important for a growing up child. Discuss the kind of learning that supports it.
Answer: Observational learning: The acquisition of new forms of behaviour, information or concepts through exposure to others and the consequences they experience is called observational learning. This learning is also called social learning because we human beings learn many simple and complex social skills through observations.The concept of social learning was introduced by BANDURA.
Characteristics of observational learning

• Individualsleam social behaviour of person of status, respect and behave similarly when put in specific social situation e.g. In games, children quite often use.
• For such learning only those persons are observed who are considered to be as role models.
• Social behaviours are learned by observation.
• Personality characteristics, habits are developed through observational learning.

Concept of modeling

• According to social learning much of what human beings learn through direct experience can be learned through watching someone. It is because of modeling.
• Observational learning observers acquire knowledge by observing the model’s behaviour, but performance is influence by model’s behaviour being rewarded or punished. 1
• Children of fearful parents become fearful, children of critical parents become critical and children who observe confident adults tend to become confident themselves.

Influence of modeling

• It can be well understood by studies conducted by BANDURA.
• He showed a 5 minute film to children. The film showed numerous dolls including bobo dolls in a play room. The film had three versions:
  1st group of children see a boy being punished for his aggressive behaviour while playing.
  2nd group of children see boy being rewarded and praised by adult for being aggressive to the doll.
  3rd group of children see nothing, neither the boy being rewarded nor punished for aggressive behaviour displayed.
• It was found that those children who displayed aggressive behaviour being rewarded were most Aggressive, those who had seen aggressive model being punished were least aggressive.

Conclusion
In observational learning, observers require knowledge by observing model’s behaviour but performance is influenced by model’s behaviour being rewarded or punished.

Question 5. Explain the procedures for studying verbal learning.
Answer: Verbal Learning: The process of learning to respond verbally to verbal stimulus, which may include symbols, nonsense syllables and lists of words.
Procedures for studying verbal learning are:

1. Paired—Associated learning:
   • This method is similar to S-S conditioning and S-R learning.
   • When the list of paired-associates is prepared, the first word of the pair is used as the stimulus and the second word as the response.
   • The first members of the pairs (stimulus term) are nonsense syllables (consonant-vowel-consonant), and the second are English nouns (response term).
     e.g.: Stimulus = Response
     Gen = Loot
     Dem= Time
     Div= Lamp
   • The learner is first shown both the stimulus response pairs together and is instructed to remember and recall the response after the presentation of each stimulus term. After that a learning trial begins.
   • Trials continue until the participant gives all the response words without a single error.
2.  Serial learning:
   • First, lists of verbal items, i.e. nonsense syllables, most familiar or least familiar words, interrelated words etc. are prepared.
   • In serial learning the participant is presented the entire list and is required to produce the items in the same serial order as in the list.
   • Learning trials continue until the participant correctly anticipates and recall in the given order.
3. Free Recall:
   • In this method, participants are presented a list of words, each word is shown at a fixed rate of exposure duration.
   • Immediately after the presentation of the list, the participants are required to recall the words in any order they can.

This method is used to study how participants organize words for storage in memory.
Studies also indicate that the items placed in the beginning or end of the lists are easier to recall than those placed in the middle which are more difficult to recall.

Question 6. What is a skill? What are the stages through which skill learning develops?
Answer: A skill is defined as the ability to perform some complex task smoothly and efficiently, e.g.: car driving, writing etc.
Skill consists of a chain of perceptual motor responses or as a sequence of S-R associations, e.g.: Movements of legs, feet and toes etc.
According to Fitts skill learning develops through three stages:

1. Cognitive Phase: In cognitive phase of skill learning, the learner has to understand and memorise the instructions.
   • The learner has to understand how the task has to be performed.
   • In this phase every outside cue instructional demand, and one’s response outcome have to be kept alive in consciousness.
2. Associative Phase:
   • Different sensory inputs or stimuli are to be linked with appropriate responses.
   • As the practice increases, errors decrease, performance improves and time taken is also reduced.
3. Autonomous Phase: two important changes take place in performance.
   • The Attentional demands of the associative phase decreases.
   • Inference created by external factors reduces. Finally, skilled performance attains Automaticity with minimal demands of – conscious effort.

Question 7. How can you distinguish between generalisation and discrimination?
Answer:  Generalisation:

• Pavlov noticed that when a C.S – C.R. bond has been established by conditioning, a stimulus which is similar to the C.S can produce the same response and he called this stimulus Generalisation, or in other words Generalisation occurs due to similarity.
  e.g. If the dog is conditioned to salivate to tone, it will salivate to any type of tone , like electric bell, worship bell, college bell, buzzer and other sounds.
• Stimulus Generalisation in conditioning happens usually more in childhood particularly when the child has not developed the capacity to differentiate between two stimuli.
  For example; During infancy the baby considers every woman to be his mother.

Discrimination:

• Discrimination is the process of learning to make one response to one stimulus and another response – or no response to another stimulus.
  e.g: discrimination can be obtained in classical conditioning by pairing one stimulus (the CS+) with an unconditioned stimulus and never pairing another stimulus (the CS) with the unconditioned stimulus.
• Discrimination is a response due to difference or in other words discriminative response depends on the discrimination capacity or discrimination learning of an organism.

Question 8. How does transfer of learning takes place?
Answer: Transfer of learning refers to the way in which we might transfer skills learned in one situation to a second, related situation. Thus, learning to play tennis may introduce a range of coordination and racket skills that would then transfer to similar games such as squash.

• It refers to the effects of prior learning on new learning.
• Transfer is consider to be positive if the earlier learning facilitates current learning. If new learning is a related then it is consider to be negative transfer.
• Absence of facilitative of retarding effect means zero transfer i.e. earlier learning has no effect on later learning.

Question 9. Why is motivation a prerequisite for learning?
Answer: Motivation is considered a pre-requisite and acts as a main facilitator of learning.

1. It is a mental as well as a physiological state, which arouses an organism to act for fulfilling the current need.
2. Motivation energises an organism to act rigorously for attaining some goal, and such sets persist until the goal is attained and the need is satisfied.
   e.g.: The more motivated you are the more hard work you do for learning.
3.  Motivation for learning arises from two sources:
   • Intrinsic motivation: One may learn many things because he/she enjoys them or it provides the means for attaining some other goal.
   • Extrinsic motivation: Throughout the session one learn to acquire knowledge and skill, which may help to get a good job later.

Question 10. What does the notion of preparedness for learning mean?
Answer: Preparedness is a reference to the fact that organisms are better able to associate certain combination of stimuli, responses and reinforces than others.

• If an animal eats and is then ill, it may develop an aversion to the flavor of the food, but not to visual or auditory stimuli that works present at the same time.
• The members of different species are very different from one another in their capacities and response abilities.
• The kinds of S-S or S-R learning an organism can easily acquire depends on the associative mechanism it is genetically endowed with or prepared for.
• A particular kind of associative learning is easy for apes or human beings but may be extremely difficult for another species.
• It implies that learning very much dependent on those association for which one is genetically prepared at the same time on his/her psychological preparedness to learn a particular task.

In This Post we are  providing  CHAPTER 1 WHAT IS PSYCHOLOGY? NCERT MOST IMPORTANT QUESTION for Class 11 PSYCHOLOGYwhich will be beneficial for students. These solutions are updated according to 2021-22 syllabus. These   can be really helpful in the preparation of Board exams and will provide you with a brief knowledge of the chapter.

NCERT MOST IMPORTANT QUESTION ON WHAT IS PSYCHOLOGY?

Question 1. What is behaviour? Give examples of overt and covert behaviour?
Answer:  Behaviour refers to any response of an organism that can be measured. Any covert or overt action/reaction a person does that can be observed in some ways.
A person running to catch train is an example of overt behaviour.
The working of human memory or problem solving might be thought of as behaviour, even though they cannot be observed directly but must be inferred from their product.

Question 2. How can you distinguish scientific psychology from the popular notions about the discipline of Psychology?
Answer:  The popular theories of human behaviour are based on common sense and may or may not be true if investigated scientifically.

• Common sense based on hind sight. Psychology as a science looks for patterns of behaviour which can be predicted and not explained after the behaviour occurs.
• Dweck’s study on children (who gave up too easily when faced with difficult problems or failures) is worth mentioning here.
• Commonsense tells us to give them easy problems, first in order to increase their success rate so that their confidence goes up.
• Dweck found that children who had always succeeded because they were given easy problems could not cope up with difficult problems and gave up faster in comparison to those who had experience of both success and failure and were taught to put more effort to deal with difficult problems.Such studies prove that predictions based on empirical studies are reliable and valid.

Question 3. Give a brief account of the evolution of psychology.
Answer:  Psychology as a modem discipline has a short history but a long past. It grew out of ancient philosophy. It emerges as a scientific discipline in the following phases:
1. Structuralism:
It is the oldest school/approach to psychology, and it was proposed by William Wundt. Structuralists were interested in analysis of human mind and its structure.

• They were interested in conscious experience and wanted to study the building blocks of mind.
• They used introspective method to study mental processes and experiences.

2. Functionalism:
It is an approach to psychology, developed by an American Psychologist William James.

• They (Functionalists) emphasised on what the mind does and the function of consciousness in adjustment to the environment
• According to them consciousness is an on-going stream of mental process, it can’t be broken down into parts.
• They also used introspective method to study mental processes and experiences.

3. Behaviourism:
Proposed by John B. Watson who viewed psychology as the science of behaviour and behaviour could be described objectively in terms of stimuli and responses (S-R).

• This approach proposed that mentalist concepts such as consciousness, image or mind cannot be measured or studied objectively and scientifically.
• Watson emphasised on observable and verifiable response to stimuli.
• He was influenced by Pavlov’s classical conditioning and was interested in the study of learning.

4. Gestalt Psychology:
This approach was a revolt against structuralism, founded in Germany by Wertheimer, Kohler and Koffka

• It focused on perceptual organisation (organisation of what we see) and they also demonstrated the laws of perceptual organisation.
• Structuralist wanted to break down perception into elements but Gestalt stated that when we look at the world, our perceptual experience is more than the sum of the components of the perceptions i.e. we give meaning to perception.
• For example, when we look at a table we do not see four wooden legs and trapezoid plain surface above it but we recognise it as a table.

5. Psychoanalysis:
This approach was proposed by Dr. Sigmund Freud.

• He viewed human behaviour as a dynamic manifestation of unconscious desires and conflicts of which we are not aware at present.
• He used psychoanalysis as a system to understand and cure psychological disorders.

6. Humanism:
It was advocated by Carl Rogers and Abraham Maslow.

• They emphasised on the free will of human beings i.e. people are free to do whatever they choose to do. Their actions are not predetermined by any force.
• They said that human beings strive to grow and unfold their inner potential i.e. what they are capable of doing.
• According to them all individuals have innate tendency to self actualise and all human activities are goal directed and worthwhile.

7. Cognitive Perspective/Cortstructivism:
This perspective is a combination of Gestalt approach and structuralist approach.
This approach focuses on cognition i.e. how we know the world through thinking understanding, perceiving, memorising and problem solving etc.

• Jean Piaget and Vygotsky are the pioneers of this approach.
• Cognitive psychologists view the human mind as an information processing system like a computer.
• Mind is considered to receive, process, transform, store and retrieve information.
• Mind is dynamic and human beings actively construct their minds as they interact with the social and physical environment and interaction between adults and children.

Question 4. What are the problems for which collaboration of psychologists with other disciplines can be fruitful? Take any two problems to explain.
Answer:  Psychology is located at the intersection of many fields of knowledge pertaining to human functioning.

• It contributes to the growth of other disciplines and draws subject-matter from them as well.
• In the study of brain and behaviour psychology shares its knowledge with neurology, physiology, biology, medicine and computer science.
• In studying the meaning, growth and the development of human behaviour in a socio-cultural context, psychology shares its knowledge with anthropology, sociology, social work, political science and economics.

Question 5. Differentiate between (a) a psychologist and a psychiatrist (b) a counsellor and a clinical psychologist.
Answer:   (a) Psychologist—A psychologist is someone who possesses the knowledge of psychology and holds recognized degree in the field; they work in diverse areas, like teaching, counselling, community etc. Psychiatrist—They are qualified medical-practitioners who are concerned with psychological well-being of individuals. Clinical Psychologist and psychiatrist are different in the qualification and in roles. Clinical Psychologist cannot administer or prescribe drugs whereas psychiatrists are medical professionals and trained in administering medicine/drugs to treat mental disorders.
(b) Counsellor—A counsellor provides advice to the persons who suffer from motivational and emotional problems, they provide vocational guidance also. Clinical psychologist—A clinical psychologist also helps people with behavioural, mental and emotional problems.

• They are post- graduate in Psychology and are specialised professionals.
• They provide therapy for various mental disorders, anxiety, fear or stress of any type.
• They use interview and administer psychological tests to diagnose the client’s problem.

Question 6. Describe some of the areas of everyday life where understanding of psychology can be put to practice. 
Answer: 

• Psychology is not only a subject that satisfies curiosities of our mind about human nature, but it is also a subject that offers solutions to a variety of problems. It ranges from personal to family, a community or even national and international dimensions.
• The solution of these problems may involve political, economic and social reforms; however, these problems are a result of unhealthy thinking, negative attitude towards people and self and undesirable patterns of behaviour.
• A psychological analysis of these problems helps both in having a deeper understanding of these problems and also finding effective solutions.
• Psychology enables an individual to understand oneself in a balanced and positive way without being reactionary, in order to deal with everyday challenges and meet with personal expectations.
• Therefore, understanding of psychology enables a person to build stronger relationships at community level and improve individual strength.

Question 7. How can knowledge of the field of environmental psychology be used to promote environment friendly behaviour?
Answer:  Environmental psychology studies the interaction between natural and man-made environment and human behaviour.

• The knowledge of environmental psychology can help us prevent big disasters.
• We can learn to modify our behaviour to prevent any unwanted and painful outcome.
• For example, if we know the hazards of growing population, we can certainly apply some measure to stop population growth.

Question 8. In terms of helping solve an important social problem such as crime, which branch of psychology do you think is most suitable. Identify the field and discuss the concerns of the psychologists working in this field.
Answer:  The branch of social psychology is the most suitable for solving problems like crime.
It explores through thought process of people and their influence on other. Social psychologists are concerned with topics like attitude, conformity, obedience to authority, social motivation, inter-group relations, etc.
In answering such questions the knowledge of psychology for Lawer and a criminologist is also very essential. If they have the knowledge of psychology they can understand how well a witness remembers the incident? How well can he/she report such facts when taking the witness stand in the court.

Question 9.Lata Mangeshkar is an accomplished singer in the Indian cinema. Name the need which best represents this case in the Maslow’s hierarchy of needs.

Answer: self-actualisation

Question 10.When we go to a matinee show, on entering the theatre we find it difficult to see things around. However, after spending about 15-20 minutes there, we are able to see almost everything. What is this phenomenon called?

Answer:visual adaptation.

In This Post we are  providing  CHAPTER 7 INTRODUCING TO REMOTE SENSING NCERT MOST IMPORTANT QUESTION for Class 11 GEOGRAPHY which will be beneficial for students. These solutions are updated according to 2021-22 syllabus. These   can be really helpful in the preparation of Board exams and will provide you with a brief knowledge of the chapter.

NCERT MOST IMPORTANT QUESTION ON INTRODUCING TO REMOTE SENSING

Question 1.
All images are not photographs but all photographs are images. How?
Answer:
An image refers to pictorial representation, regardless of what regions of energy have been used to detect and record it. A photograph refers specifically to images that have been recorded on photographic film. Therefore, all images are not photographs but all photographs are images.

Question 2.
What is temporal resolution?
Answer:
In satellite remote sensing, the sun-synchronous polar orbit enables the collection of images after a pre-determined periodical interval. This interval is referred to as the temporal resolution or the revisit time of the satellite over the same area of the earth surface.

Question 3.
What is a scanner? How does it work?
Answer:
A scanner is usually made up of a reception system consisting of a mirror and detectors. A scanning sensor constructs the scene by recording a series of scan lines. While doing so, the motor device oscillates the scanning mirror through the angular field of view of the sensor, which determines the length of scan lines and is called swath. It is because of such reasons that the mode of collection of images by scanners is referred bit-by-bit. Each scene is composed of cells that determine the spatial resolution of an image. The oscillation of the scanning mirror across the scene directs the received energy to the detectors, where it is converted into electrical signals. These signals are further converted into numerical values called Digital Number (DN Values) for recording on a magnetic tape.

Question 4.
Explain about different types of sensor resolutions.
Answer:
Remote sensors are characterised by spatial, spectral and radiometric resolutions that enable the extraction of useful information pertaining to different terrain conditions.

1. Spatial Resolution: Spatial resolution of the sensors refers to the capability of the sensor to distinguish two closed spaced object surfaces as two different object surfaces. As a rule, with an increasing resolution the identification of even smaller object surfaces become possible,

2. Spectral Resolution: It refers to the sensing and recording power of the sensor in different bands of EMR (Electromagnetic radiation). Multispectral images are acquired by using a device that disperses the radiation received by the sensor and recording it by deploying detectors sensitive to specific spectral ranges. The principles in obtaining such images is the extension of the dispersion of light in nature resulting in the appearance of the “rainbow”.

3.Radiometric Resolution: It is the capability of the sensor to discriminate between two targets. Higher the radiometric resolution, smaller the radiance differences that can be detected between two targets.

Question 5.
How can we classify the characteristics of an object?
Answer:
We can group the characteristics of the objects into two broad categories, i.e. image characteristics and terrain characteristics.

• Image Characteristics: The image characteristics include tone or colour in which objects appear, their shape, size, pattern, texture and the shadow they cast.
• Terrain Characteristics: Location and the association of different objects with their surrounding objects constitute the terrain characteristics.

Question 6.
Differentiate between:
(i) Photographs and images.
Answer:

Basis	Photograph	Image
Meaning	A photograph refers specifically to images that have been recorded on photographic film.	An image refers to pictorial representation, regardless of what regions of energy have been used to detect and record it.
Scope	All photographs are images. Therefore it is inclusive in images and its scope is narrow.	All images are not photographs. Images can be: digital images and photographic images. Therefore, its scope is wider.

(ii) Whiskbroom Scanners and Pushbroom Scanners.
Answer:
Whiskbroom scanners, also sometimes referred to as spotlight or across track scanners, use a mirror to reflect light onto a single detector. The mirror moves back and forth, to collect measurements from one pixel in the image at a time. It is shown below:

The moving parts make this type of sensor expensive and more likely to wear out.

Pushbroom Scanners:
Pushbroom scanners are also sometimes referred to as along track scanners. It is used a line of detectors arranged perpendicular to the flight direction of the spacecraft. As the spacecraft flies forward, the image is collected one line at a time, with all of the pixels in a line being measured simultaneously. It is shown with the help of following figure. A pushbroom scanner receives a stronger signal than a whiskbroom scanner because it looks at each pixel area for longer. One drawback of pushbroom sensors is that the detectors in the “pushbroom” can have varying sensitivity. If they are not perfectly calibrated, this can result in stripes in the data.

Sensors that use the push broom design include SPOT, IRS, QuickBird, OrbView etc.

(iii) Sun-synchronous (or polar) and geostationary orbits.
Answer:

Basis	Sun-Synchronous	Geostationary Orbits
Location	Satellites in this orbit provide medium to high resolution images of the whole earth which are mostly used for environmental monitoring. They orbit at altitudes of 300 to 1,400 km above earth.	Geostationary orbits are located about 36,000 km above the earth.
Revolution time	With every satellite orbit which takes about 90 min, the earth is rotating a bit further resulting in the fact that the satellite is “watching” different sections of the earth in narrow bands. Days or weeks later, the satellite orbits again above the same section.	At this altitude a satellite needs exactly 24 hours to orbit around the earth, the same time the earth takes to perform a complete revolution around its axis.
Expansion	It is expaided from 81 degree north to 81 degree south latitude.	It is expanded on one third of the globe.
Example	The US LANDSAT series is a well known example of a polar orbiting satellite.	METEOSAT is one example for a geostationary satellite.
Utility	It is important for earth resources	It is important for tele­communication and weather department.

(iv) Photographic and non-photographic sensors.
Answer:

Basis	Photographic sensors	Non-photographic Sensors
Meaning	A photographic sensor (camera) records the images of the objects at an instance of exposure.	A non-photographic sensor obtains the images of the objects in bit-by-bit form. These sensors are known as scanners.
Device	It is done through camera	It is done through scanners
Other name	It is also called Analogue sensors	It is also called digital sensors.

(v) Photographic image and digital image
Answer:

Basis	Photographic Image	Digital Image
Meaning	Photographs are acquired in the optical regions of the electromagnetic spectrum, i.e. 0.3 – 0.9 pm.	A digital image consists of discrete picture elements called pixels. Each one of the pixels in an image has an intensity value and an address in two­ dimensional image space.
Colour	Four different types of light sensitive film emulsion bases are used to obtain photographs. These are black and white, colour, black and white infrared and colour infrared.	It does not require any film.

Question 7.
How does remote sensing help in the collection of information about the properties of the objects and phenomena of the earth surface?
Answer:
Remote sensing help in the collection of information about the properties of the objects and phenomena of the earth surface:

1. Source of Energy: Sun is the most important source of energy used in remote sensing.

2. Transmission of Energy from the Source to the Surface of the Earth:
The energy that emanates from a source propagates between the source and the object surface in the form of waves of energy at a speed of light (300,000 km per second). Such energy propagation is called Electromagnetic Radiation (EMR).

3. Interaction of Energy with the Earth’s Surface: The propagating energy finally interacts with the objects of the surface of the earth. This leads to absorption, transmission, reflection or emission of energy from the objects.

4. Propagation of Reflected/Emitted Energy through Atmosphere: When energy is reflected from objects of the earth’s surface, it re-enters into the atmosphere.

5. Detection of Reflected/Emitted Energy by the Sensor: The sensors recording the energy that they receive are placed in a near-polar sun-synchronous orbit at an altitude of 700 – 900 km. These satellites are known as remote sensing satellites (e.g. Indian Remote Sensing Series). As against these satellites, the weather monitoring and telecommunication satellites are placed in a Geostationary position (the satellite is always positioned over its orbit that synchronizes with the direction of the rotation of the earth) and revolves around the earth (coinciding with the direction of the movement of the earth over its axis) at an altitude of nearly 36,000 km (e.g. INSAT series of satellites).

6. Conversion of Energy Received into Photographic/Digital Form of Data: The radiations received by the sensor are electronically converted into a digital image. It comprises digital numbers that are arranged in rows and columns. These numbers may also be converted into an analogue (picture) form of data product. The sensor onboard an earth¬orbiting satellite electronically transmits the collected image data to an Earth Receiving Station located in different parts of the world.

7. Extraction of Information Contents from Data Products: After the image data is received at the earth station, it is processed for elimination of errors caused during image data collection. Once the image is corrected, information extraction is carried out from digital images using digital image processing techniques and from analogue form of data products by applying visual interpretation methods.

8. Conversion of Information into Map/Tabular Forms: The interpreted information is finally delineated and converted into different layers of thematic maps. Besides, quantitative measures are also taken to generate tabular data.

Question 8.
Explain about different types of multispectral scanners.
Answer:
In satellite remote sensing, the Multi-Spectral Scanners (MSS) are used as
sensors. These sensors are designed to obtain images of the objects while sweeping across the field of view.
The Multi-Spectral Scanners are divided into the following types:

1. Whiskbroom Scanners
2. Pushbroom Scanners

1. Whiskbroom Scanners: The whiskbroom scanners are made up of a rotating mirror and a single detector. The mirror is so oriented that when it completes a rotation, the detector sweeps across the field of view between 90° and 120° to obtain images in a large number of narrow spectral bands ranging from visible to middle infrared regions of the spectrum. The total extent of the oscillating sensor is known as the Total Field of View (TFOV) of the scanner. While scanning the entire field, the sensor’s optical head is always placed at a particular dimension called the Instantaneous Field of View (IFOV).

2. Pushbroom Scanners: The pushbroom scanners consist of a number of detectors which are equivalent to the number obtained by dividing the swath of the sensor by the size of the spatial resolution. In pushbroom scanner, all detectors are linearly arrayed and each detector collects the energy reflected by the ground cell (pixel) dimensions of 20 metres at a nadir’s view. For example, the swath of High-Resolution Visible Radiometer – 1 (HRVR – 1) of the French remote sensing satellite SPOT is 60 km and the spatial resolution is 20 metres. If we divide 60 km x 1000 metres/20 metres, we get a number of 3000 detectors that are deployed in SPOT HRV – 1 sensor.

Question 9.
Based upon the mechanism used in detecting and recording, in how many categories can we classify the remotely sensed data products?
Answer:
Based upon the mechanism used in detecting and recording, these may be broadly classified into two types:

1. Photographic Images
2. Digital Images

1. Photographic Images: Photographs are acquired in the optical regions of electromagnetic spectrum, i.e. 0.3-0. 9 pm. Four different types of light sensitive film emulsion bases are used to obtain photographs. These are black and white, colour, black and white infrared and colour infrared. However, in aerial photography black and white film is normally used. Photographs may be enlarged to any extent without loosing information contents or the contrast.

2. Digital Images: A digital image consists of discrete picture elements called pixels. Each one of the pixels in an image has an intensity value and an address in two-dimensional image space. A digital number (DN) represents the average intensity value of a pixel. It is dependent upon the electromagnetic energy received by the sensor and the intensity levels used to describe its range. In a digital image, the reproduction of the details pertaining to the images of the objects is affected by the size of the pixel. A smaller size pixel is generally useful in the preservation of the scene details and digital representation. However, zooming of the digital image beyond certain extent produces loss of information and the appearance of pixels only. Using a digital image processing algorithms, the digital numbers representing their intensity level in an image may be displayed.

Question 10.
Explain various elements of visual interpretation.
Answer:
Elements of Visual Interpretation Whether we are conscious of it or not we use the form, size, location of the objects and their relationships with the surrounding objects to identify them in our day-to-day life. These characteristics of objects are termed as elements of visual interpretation.

1. Tone or Colour: All objects receive energy in all regions of spectrum. The interaction of EMR with the object surface leads to the absorption, transmittance and reflection of energy. It is the reflected amount of the energy that is received and recorded by the sensor in tones of grey, or hues of colour in black and white, and colour images respectively. The variations in the tone or the colour depend upon the orientation of incoming radiations, surface properties and the composition of the objects.

2. Texture: The texture refers to the minor variations in tones of grey or hues of colour. These variations are primarily caused by an aggregation of smaller unit features that fail to be discerned individually such as high density and low density residential areas; slums and squatter settlements; garbage and other forms of solid waste; and different types of crops and plants. The textural differences in the images of certain objects vary from smooth to coarse textures.

3. Size: The size of an object as discerned from the resolution or scale of an image is another important characteristic of individual objects. It helps in distinctively identifying the industrial and industrial complexes with residential dwellings.

4. Shape: The general form and configuration or an outline of an individual object provides important clues in the interpretation of remote sensing images. The shape of some of the objects is so distinctive that make them easy to identify. For example, the shape of the Sansad Bhawan is typically distinct from many other built- up features.

5. Shadow: Shadow of an object is a function of the sun’s illumination angle and the height of the object itself. The shape of some of the objects is so typical that they could not be identified without finding out the length of the shadow they cast. For example, the Question utub Minar located in Delhi, minarets of mosques, overhead water tanks, electric or telephone lines, and similar features can only be identified using their shadow.

6. Pattern: The spatial arrangements of many natural and man-made features show repetitive appearance of forms and relationships. The arrangements can easily be identified from the images through the utilisation of the pattern they form. For example, planned residential areas with the same size and layout plan of the dwelling units in an urban area can easily be identified if their pattern is followed.

7. Association: The association refers to the relationship between the objects and their surroundings along with their geographical location. For example, an educational institution always finds its association with its location in or near a residential area as well as the location of a playground within the same premises.

In This Post we are  providing  CHAPTER 8 WEATHER INSTRUMENT, MAP AND CHARTS NCERT MOST IMPORTANT QUESTION for Class 11 GEOGRAPHY which will be beneficial for students. These solutions are updated according to 2021-22 syllabus. These   can be really helpful in the preparation of Board exams and will provide you with a brief knowledge of the chapter.

NCERT MOST IMPORTANT QUESTION ON WEATHER INSTRUMENT, MAP AND CHARTS

Question 1.
How is weather forecasting useful for different groups?
Answer:
Weather forecasting is very important for all groups:

• Weather forecasts help in taking safety measures in advance in case of the likelihood of bad weather.
• It reduces the likely loss from natural calamities. Had tsunami been predicted in advance, the loss that happened could be minimized to a great extent.
• Predicting weather a few days in advance may prove very useful to farmers and to the crew of ships, pilots, fishermen, defence personnel, etc.

Question 2.
Explain in short about Wind Vane.
Answer:
Purpose: Wind vane is a device used to measure the direction of the wind. Structure: The wind vane is a light-weight revolving plate with an arrowhead on one end and two metal plates attached to the other end at the same angle. This revolving plate is mounted on a rod in such a manner that it is free to rotate on a horizontal plane. It responds even to a slight blow of wind.
Important Aspect: The arrow always points towards the direction from which the wind blows.

Question 3.
Explain in short about Anemometer.
Answer:

An anemometer is an instrument that measures wind speed and wind pressure. Anemometers are important tools for meteorologists, who study weather patterns. They are also important to the work of physicists, who study the way air moves. The most common type of anemometer has three or four cups attached to horizontal arms. The arms are attached to a vertical rod. As the wind blows, the cups rotate, making the rod spin. The stronger the wind blows, the faster the rod spins. The anemometer counts the number of rotations, or turns, which is used to calculate wind speed. Because wind speeds are not consistent—there are gusts and lulls-wind speed is usually averaged over a short period of time.

A similar type of anemometer counts the revolutions made by windmill-style blades. The rod of windmill anemometers rotates horizontally. Other anemometers calculate wind speed in different ways. A hot-wire anemometer takes advantage of the fact that air cools a heated object when it flows over it.

Question 4.
How do Weather observatories work in India?
Answer:
Each day weather maps are prepared for that day by the Meteorological Department from the data obtained from observations made at various weather stations across the world. In India, weather-related information is collected and published under the auspices of the Indian Meteorological Department, New Delhi, which is also responsible for weather forecasting.

The Indian Meteorological Department (IMD) was established in 1875, with its headquarters at Calcutta. The IMD headquarters are presently located at New Delhi.

Question 5.
Write a short note on Stevenson Screen.
Answer:
The Stevenson screen is designed to protect thermometers from precipitation and direct sunlight while allowing air to circulate freely around them. Formation: It is made from wood with louvered sides to allow free and even flow of air. It is painted white to reflect radiation. It stands on four legs and is about 3 feet 6 inches above the level of the ground. The legs must be sufficiently rigid and be buried sufficiently in the ground to prevent shaking.

The front panel is hinged at the bottom to form a door, which allows for maintenance and reading of the thermometers. The door of Stevenson screen is always towards the north in the northern hemisphere and towards the south in the southern hemisphere because direct sunrays also affect mercury.

Objective: The purpose of the Stevenson screen is to create a uniform temperature enclosure that closely represents the same temperature as the air outside.

Question 6.
What is aneroid barometer? How does it work?
Answer:
Aneroid barometer gets its name from the Greek word, aneros in which ‘a’ means ‘not’, ‘neros’ means ‘moisture’, hence aneroid means without liquid. It is a compact and portable instrument. It consists of a corrugated metal box made up of a thin alloy, sealed completely and made airtight after partial exhaustion of air.

It has a thin flexible lid, which is sensitive to changes of pressure. As the pressure increases, the lid is pressed inward, and this, in turn, moves a system of levers connected to a pointer, which moves clockwise over the graduated dial and gives higher reading. When the pressure decreases, the lid is pushed outward and the pointer moves counter clockwise, indicating lower pressure. Barograph works on the principle of aneroid barometer.

There are a number of vacuum boxes placed one above the other so that the displacement is large. A system of levers magnifies this movement which is recorded by a pen on a paper attached to a rotating drum. The readings of a barograph are not always accurate, and therefore, they are standardised by comparing them with a mercury barometer reading.

Question 7.
Differentiate between:

(i) Wet bulb and dry bulb,
Answer:
The dry bulb and wet bulb thermometers are two identical thermometers fixed to a wooden frame. But they are different in following way:

Dry Bulb Thermometer	Wet Bulb Thermometer
It is used to measure lowest humidity	It is used to measure highest humidity.
The bulb of the dry bulb thermometer is kept uncovered and is exposed to the air	The bulb of the wet bulb thermometer is wrapped up with a piece of wet muslin, which is kept continuously moist by dipping a strand of it into a small vessel of distilled water.
Its temperature remains high.	The evaporation from the wet bulb lowers its temperature.

(ii) Aneroid Barometer and Mercury Barometer.
Answer:

Aneroid Barometer	Mercury Barometer
Aneroid barometer gets its name from the Greek word, aneros in which ‘a’ means ‘not’, ‘neros’ means ‘moisture’, hence aneroid means without liquid. It is a compact and portable instrument.	Mercury barometer is an accurate instrument and is used as a standard. In it the atmospheric pressure of any place is balanced against the weight of a column of mercury in an inverted glass tube.
It is filled with alcohol	It is filled with mercury
It is used to measure lowest temperature.	It is used to measure highest temperature.

(iii) Centigrade and the Fahrenheit.
Answer:
Both are units of measuring temperature but they have some differences.

Centigrade	Fahrenheit
On the Centigrade thermometer, the temperature of melting ice is marked 0°C and that of boiling water as 100°C, and the interval between the two is divided into 100 equal parts.	On the Fahrenheit thermometer, the freezing and boiling points of water are graduated as 32°F and 212°F respectively.
Centigrade = (Fahrenheit -32)	Fahrenheit= Centigrade ×\frac { 9 }{ 5 } +32

Question 6.
How is information about weather and related facts collected organized and dispensed in India?
Answer:

In India, weather-related information is collected and published under the auspices of the Indian Meteorological Department, New Delhi, which is also responsible for weather forecasting.

A typical surface observatory has instruments for measuring and recording weather elements like temperature (maximum and minimum), air pressure, humidity, clouds, wind and rainfall. Specialised observatories also record elements like radiation, ozone atmospheric trace gases, pollution and atmospheric electricity. These observations are taken all over the globe at fixed times of the day as decided by the WMO and the use of instruments are made conforming to international standards, thus making observations globally compatible. In India, meteorological observations are normally classified into five categories depending upon their instruments and the number of daily observations taken. The highest category is Class-I.

Typical instrumental facility available in a Class-I observatory consists of the following:

• Maximum and minimum thermometers
• Anemometer and wind vane
• Dry and Wet bulb thermometer
• Rain gauge
• Barometer

Observations are taken in these observatories normally at 00,03,06,09, 12,15,18,21 hours (Greenwich Mean Time) around the globe. However, for logistic reasons, some of the observatories take limited number of daily observations upper air observation during daytime only.

Weather satellites make comprehensive and large-scale observations of different meteorological elements at the ground level as well in the upper layers of the atmosphere. The geo-stationary satellites provide space-based observations about weather conditions. The Indian National Satellite (INSAT) provides valuable observations of temperature, cloud cover, wind and associated weather phenomena.

Question 7.
Explain the working of a barometer.
Answer:
The instrument used to measure atmospheric pressure is called a barometer. The unit of measurement is in the millibar. The most commonly used barometers are the mercury barometer, aneroid barometer and barographs. All the three work differently. Their working is explained below briefly:

1. Mercury barometer: It is an accurate instrument and is used as a standard. In it the atmospheric pressure of any place is balanced against the weight of a column of mercury in an inverted glass tube.

2.Aneroid barometer: It is a compact and portable instrument. It consists of a corrugated metal box made up of a thin alloy, sealed completely and made airtight after partial exhaustion of air. It has a thin flexible lid, which is sensitive to changes of pressure. As the pressure increases, the lid is pressed inward, and this, in turn, moves a system of levers connected to a pointer, which moves clockwise over the graduated dial and gives higher reading. When the pressure decreases, the lid is pushed outward and the pointer moves counter clockwise, indicating lower pressure.

3. Barograph: It works on the principle of aneroid barometer. There are a number of vacuum boxes placed one above the other so that the displacement is large. A system of levers magnifies this movement which is recorded by a pen on a paper attached to a rotating drum. The readings of a barograph are not
always accurate, and therefore, they are standardised by comparing them with a mercury barometer reading.

Question 8.
Write short notes on the following:
(i) Safe place for a thermometer
(ii) Indian Daily Weather report
Answer:
(i) Safe place for thermometer: It is not safe to keep a thermometer in sunlight. We should also not keep it in airtight surroundings. The Stevenson screen is designed to protect thermometers from precipitation and direct sunlight while allowing air to circulate freely around them. It is made from wood with louvered sides to allow free and even flow of air. It is painted white to reflect radiation. The purpose of the Stevenson screen is to create a uniform temperature enclosure that closely represents the same temperature as the air outside.

It stands on four legs and is about 3 feet 6 inches above the level of the ground. The legs must be sufficiently rigid and be buried sufficiently in the ground to prevent shaking. The front panel is hinged at the bottom to form a door, which allows for maintenance and reading of the thermometers. The door of Stevenson screen is always towards the north in the northern hemisphere and towards the south in the southern hemisphere because direct sunrays also affect mercury.

(ii) Indian Daily Weather Report: IMD became a member of the World Meteorological Organization after independence on 27 April 1949. The agency has gained in prominence due to the significance of the monsoon rains on Indian agriculture. It plays a vital role in preparing the annual monsoon forecast, as well as in tracking the progress of the monsoon across India every season.

IMD undertakes observations, communications, forecasting and weather services. In collaboration with the Indian Space Research Organisation, the IMD also uses the IRS series and the Indian National Satellite System (INSAT) for weather monitoring of the Indian subcontinent. IMD was the first weather bureau of a developing country to develop and maintain its own satellite system. IMD is one of the 6 worldwide Regional Specialized Meteorological Centers of the Tropical Cyclone Programme of the World Weather Watch of the World Meteorological Organization. It is regional nodal agency for forecasting, naming and disseminating warnings about tropical cyclone in the Indian Ocean north of the Equator.

Question 9.
Explain the history of weather forecasting in India.
Answer:
In 1686, Edmond Halley published his treatise on the Indian summer monsoon, which he attributed to a seasonal reversal of winds due to the differential heating of the Asian land mass and the Indian Ocean. The first meteorological observatories were established in India by the British East India Company. These included the Calcutta Observatory in 1785, the Madras Observatory in 1796 and the Colaba Observatory in 1826. Several other observatories were established in India during the first half of the 19th century by various provincial governments.

After a tropical cyclone hit Calcutta in 1864, and the subsequent famines in 1866 and 1871 due to the failure of the monsoons, it was decided to organise the collection and analysis of meteorological observations under one roof.
As a result, the Indian Meteorology Department was established in 1875. Henry Francis Blanford was appointed the first Meteorological Reporter of the IMD. In May 1889,Sir John Eliot was appointed the first Director General of Observatories in the erstwhile capital, Calcutta. The IMD headquarters were later shifted to Shimla in 1905, then to Pune in 1928 and finally to New Delhi in 1944.

Question 10.
Explain the instruments used to measure atmospheric pressure.
Answer:
A barometer is a scientific instrument used in meteorology to measure atmospheric pressure. A simple barometer consists of a long glass tube (closed at one end, open at the other) filled with mercury and turned upside down into a container of mercury. The barometer works by balancing the mercury in the glass tube against the outside air pressure, just like a set of scales. As air pressure increases—that is, as the air becomes heavier—it pushes more of the mercury up into the tube. As air pressure decreases, more of the mercury drains from the tube. So the level of mercury in the tube provides a precise measure of air pressure.

Mercury barometer is . an accurate instrument and is used as a standard. In it the atmospheric pressure of any place is balanced against the weight of a column of mercury in an inverted glass tube. Aneroid barometer is a compact and portable instrument. It consists of a corrugated metal box made up of a thin alloy, sealed completely and made airtight after partial exhaustion of air. It has a thin flexible lid, which is sensitive to changes of pressure. As the pressure increases, the lid is pressed inward, and this, in turn, moves a system of levers connected to a pointer, which moves clockwise over the graduated dial and gives higher reading.

When the pressure decreases, the lid is pushed outward and the pointer moves counterclockwise, indicating lower pressure. Barograph works on the principle of aneroid barometer. There are a number of vacuum boxes placed one above the other so that the displacement is large. A system of levers magnifies this movement which is recorded by a pen on a paper attached to a rotating drum. The readings of a barograph are not always accurate, and therefore, they are standardised by comparing them with a mercury barometer reading.

In This Post we are  providing  CHAPTER 6 INTRODUCTION TO AERIAL PHOTOGRAPHS NCERT MOST IMPORTANT QUESTION for Class 11 GEOGRAPHY which will be beneficial for students. These solutions are updated according to 2021-22 syllabus. These   can be really helpful in the preparation of Board exams and will provide you with a brief knowledge of the chapter.

NCERT MOST IMPORTANT QUESTION ON INTRODUCTION TO AERIAL PHOTOGRAPHS

Question 1.
Compute the scale of an aerial photograph when the flying height of the aircraft is 7500 m and the focal length of the camera is 15 cm.
Answer:
Focal Length (f) : Flying Height (H) = Photo distance (Dp) : Ground distance (Dg)
Sp = f: H
Or Sp = 15 cm : 7,500 x 100 cm
Or Sp = 1 : 750,000/15
Therefore, Sp = 1 : 50,000

Question 2.
Differentiate between:
(i) Aerial photograph and map.
(it) Aerial photographs and satellite images.
(iii) High oblique photograph and low oblique photograph.
(iv) Vertical photograph and high oblique photograph.
(v) Vertical photograph and low oblique photograph.
Answer:
(i)

Basis	Aerial Photograph	Map
Projection	It is a central Projection.	It is an orthogonal Projection.
Accuracy	An aerial photograph is geometrically incorrect. The distortion in the geometry is minimum at the centre and increases towards the edges of the photographs.	A map is geometrically correct representation of the part of the earth projected.
Scale	The scale of the photograph is not uniform.	The scale of the map is uniform throughout the map extent.
Impact of enlargement or reduction	Enlargement/reduction does not change the contents of the photographs and can easily be carried out.	Enlargement/reduction of the maps involves redrawing it afresh.
Utility	Aerial photography holds good for inaccessible and inhospitable areas.	The mapping of inaccessible and inhospitable areas is very difficult and sometimes it becomes impossible.

(ii)

Basis	Aerial Photographs	Satellite Images
Meaning	These are taken from an aeroplane or helicopter.	These are taken from man-made satellite launched in space.
Accuracy	These are less accurate as compared to satellite images.	These are more accurate as compared to aerial images.
Suitability	These are suitable for taking photographs of the earth.	These are used for taking photographs of other planets and celestial bodies.
Utility	Aerial photography holds good for inaccessible and inhospitable areas of the earth	It is useful in knowing climatic condition and weather forecast.
Disastermanagement	It is more useful in disaster management for providing relief.	It is more useful in disaster management by predicting weather and taking preventive actions.

(iii)

Basis	High Oblique Photograph	Low Oblique Photograph
Optical Axis	Deviation is more than 300 degree from the vertical axis.	Deviation is more than 30 degree from the vertical axis.
Coverage	It covers largest area.	It covers larger area.
Difference in comparison to map	It is greatest with high oblique photographs.	It is greater with low oblique photographs.
Utility	It is useful in illustrative comparison.	It is useful in recoqnaissance survey.

(iv)

Basis	Vertical Photograph	High Oblique Photograph
Optical Axis	Tilt< 3 degree i.e. exactly or nearly coincides with the vertical axis.	Deviation is more than 300 degree from the vertical axis.
Horizon	Horizon does not appear	Horizon does appear
Coverage	It covers small area.	It covers largest area.
Scale	Scale is uniform if the terrain is flat.	Scale keeps decreasing from foreground to background.
Difference in comparison to map	It is least with vertical photographs.	It is greatest with high oblique photographs.
Utility	It is useful in topographical and thematic mapping.	It is useful in illustrative comparison.

(v)

Basis	Vertical Photograph	Low Oblique Photograph
Optical Axis	Tilt< 3 degree i.e. exactly or nearly coincides with the vertical axis.	Deviation is more than 30 degree from the vertical axis.
Horizon	Horizon does not appear	Horizon does appear
Coverage	It covers small area.	It covers comparatively larger area.
Scale	Scale is uniform if the terrain is flat.	Scale keeps decreasing from foreground to background.
Difference in comparison to map	It is least with vertical photographs.	It is relatively greater with low oblique photographs.
Utility	It is useful in topographical and thematic mapping.	It is useful in reconnaissance survey.

Question 3.
Explain about different types of aerial photographs on the basis of position of camera axis.
Answer:
Types of Aerial Photographs Based on
the Position of the Cameral Axis:
1. Vertical Photographs: While taking aerial photographs, two distinct axes are formed from the camera lens centre, one towards the ground plane and the other towards the photo plane. The perpendicular dropped from the camera lens centre to the ground plane is termed as the vertical axis, whereas the plumb line drawn from the lens centre to the photo plane is known as the photographic/optical axis. When the photo plane is kept parallel to the ground plane, the two axes also coincide with each other. The photograph so obtained is known as vertical aerial photograph

2. Low Oblique: An aerial photograph
taken with an intentional deviation of 15° to 30° in the camera axis from the vertical axis is referred to as the low oblique photograph. This kind of photograph is often used in reconnaissance surveys. It is shown with the help of following figure.

3. High Oblique: The high oblique are photographs obtained when the camera axis is intentionally inclined about 60° from the vertical axis. Such photography is useful in illustrative surveys. It is shown with the help of following figure.

Question 4.
How can we classify aerial photographs on the basis of scale?
Answer:
There are three types of Aerial Photographs Based on Scale.

1. Large Scale Photographs: When the scale of an aerial photograph is 1:15,000 and larger, the photography is classified as large-scale photograph. It is shown with the help of following figure.
   
2. Medium Scale Photographs: The aerial photographs with a scale ranging between 1 : 15,000 and 1 : 30,000 are usually treated as medium scale photographs as shown in the figure given below:
   
3. Small Scale Photographs: The
   photographs with the scale being smaller than 1 : 30,000, are referred to as small scale photographs as shown in the figure.
   

Question 5.
Explain in detail about aerial photographs and satellite images.
Answer:
These days, it has become very easy to draw’ maps and interpret them through aerial photographs and satellite images. It requires a special type of training to understand and interpret aerial photographs. Many countries are making use of aerial photographs not only for defence purposes but also for planning land use, development of cities and towns, development of multipurpose projects etc.

Satellite images are used to predict climatic conditions. It becomes easy to predict weather by using satellite images, wre can find mineral availability, land use plan by making use of satellite images.

Question 6.
Explain different types of projection.
Answer:
There are three types of projection:
1. Parallel Projection: In this projection, the projecting rays are parallel but not necessarily perpendicular. The triangle ABC is projected on LL1 as triangle abc.

2. Orthogonal Projection: This is a special case of parallel projections. Maps are orthogonal projections of the ground. The advantage of this projection is that the distances, angles or areas on the plane are independent of the elevation differences of the objects. In the figure given below an orthogonal projection is where the projecting rays are perpendicular to the line LL1

3. Central Projection: Figure given below shows an example of Central Projection. In this figure the projecting rays Aa, Bb and Cc pass through a common point O, which is called the perspective Centre. The image projected by a lens is treated like a central projection. An aerial photograph, as discussed earlier is a central projection. In an absolutely vertical flat terrain the aerial photograph will be geometrically the same as the corresponding map of the area. However, because of the tilt of the photograph and relief variations of the ground photographed, an aerial photograph differs geometrically from the map of the corresponding area.

Class 11 Practical Work in Geography Chapter 6 Viva Questions

Question 7.
Name three agencies eligible to take aerial photographs in India.
Answer:
In India three flying agencies are officially permitted to carry out aerial photography. They are:

1. Indian Air Force,
2. Air Survey Company, Kolkata and
3. National Remote Sensing Agency, Hyderabad.

These are identified on the aerial photographs as A, B and C respectively.

Question 8.
How can aerial photograph be used to derive the photo scale formula?
Answer:
Aerial photograph may be used to derive the photo-scale formula in the following way:
Focal Length (f): Flying Height (H) = Photo distance (Dp): Ground distance (Dg).

Question 9.
How can scale of aerial photographs be obtained by establishing relationship between Photo Distance and Ground Distance?
Answer:
If additional information like ground distances of two identifiable points in an aerial photograph is available, the corresponding ground distances is expressed by Dg and for which the distances on an aerial photograph is expressed as Dp. Both are measured. In such cases, the scale of an aerial photograph will be measured as a ratio of the two, i.e. Dp/ Dg.

Question 10.
Explain how can scale of aerial photograph be measured by establishing relationship between Photo Distance and Map Distance?
Answer:
The distances between different points on the ground are not always known. However, if a reliable map is available for the area shown on an aerial photograph, it can be used to determine the photo scale. In other words, the distances between two points identifiable both on a map and the aerial photograph enable us to compute the scale of the aerial photograph (Sp).

The relationship between the two distances may be expressed as under: (Photo scale: Map scale) = (Photo distance : Map distance) We can derive Photo scale (Sp) = Photo distance (Dp): Map distance (Dm) x Map scale factor (msf).

In This Post we are  providing  CHAPTER 2 MAP SCALE NCERT MOST IMPORTANT QUESTION for Class 11 GEOGRAPHY which will be beneficial for students. These solutions are updated according to 2021-22 syllabus. These   can be really helpful in the preparation of Board exams and will provide you with a brief knowledge of the chapter.

NCERT MOST IMPORTANT QUESTION ON MAP SCALE

Question 1.
What are advantages of representative fraction?
Answer:
Representative fraction can be used in all countries whether we are acquainted with their unit system or not. Therefore, it is also called universal method of scale.

Question 2.
Explain about the importance of scale.
Answer:
A map scale provides the relationship between the map and the whole or a part of the earth’s surface shown on it. We can also express this relationship as a ratio of distances between two points on the map and the corresponding distance between the same two points on the ground.

Question 3.
What is the unit in representative fraction?
Answer:
There is no unit in representative fraction. It is only the ratio of distance on map and distance on ground.

Question 4.
What is the utility of scale in a map?
Answer:
A map scale provides the relationship between the map and the whole or a part of the earth’s surface shown on it. We can also express this relationship as a ratio of distances between two points on the map and the corresponding distance between the same two points on the ground.

1. Scale of a map determines whether it can reflect minor details on it. For example to locate Palam Vihar in Gurgaon if we locate it on world map, it will be of no use. It is better to use a map of Gurgaon to locate Palam Vihar on it.
2. On the basis of scale, maps are classified into small-scale maps and large-scale maps.

Question 5.
What factors must be kept in mind while selecting scale?
Answer:
We must consider following aspects while selecting scale:

• Purpose of map: If map is being drawn to study the minor details then we should make use of large scale maps and if it is to show physical features or large areas, we can use small scale maps as well. For example scale of a map of a house will be larger than map of a country.
• Space Available: Scale is also affected by availability of space for drawing maps.

Question 3.
Answer:

Basis	Representative Fraction	Graphical Scale
Meaning	It is a method of scale of a map or plan expressed as a fraction showing the ratio between a unit distance on the map or plan, and the distance measured in the same units on the ground.	It shows map distances and the corresponding ground distances using a line bar with primary and secondary divisions marked on it.
Impact	It gets affected by changing the size of maps.	It is not affected by changing the size of maps proportionally.
Unit	It has no unit.	It has a unit.

Question 6.
What are limitations of representative fraction?
Answer:
There are many limitations of representative fraction method. These are as follows:

• This method is only a fraction. It does not make use of any measurement system. Therefore it cannot be used to measure the direct distance between two places.
• Whenever maps are changed using computers, these fractions get changed.
• It is not easy to understand method for a layman.

Question 7.
In a scale statement it is mentioned that 1 inch represents four miles. Express it in representative fraction.
Answer:
1 inch on map represents 4 miles on ground.
Or 1 inch = 4 x 63360 ( 1 mile = 63360 inches)
1 inch = 2,53,440 inches.
Therefore 1 inch on map represents a distance of 2,53,440 inches on ground. In other words, 1 unit on map represents 2,53,440 units on ground.

Therefore Representative fraction

Question 8.
Convert Representative fraction 1:2,53,440 into a statement of scale (metric system).
Answer:
The given representative fraction can be converted into statement of scale in following steps:
1: 2,53,440 means that 1 unit on map represents 2,53,440 units on the ground. In other words, 1 cm will represent 2,53,440/1,00,000 km (because 1 km = 1,00,000 cm)
Therefore, 1 cm = 2.5344 km In statement of scale form we can say that 1 cm represents 2.5344 km.

Question 9.
Construct a graphical scale for representative fraction 1:50,000 in which distance is given in furlongs and miles.
Answer:
For graphical scale, to know the length of the line we need to make following calculations. 1:50,000 means 1 unit on map represents 50,000 units on ground.
In this way, 1 inch = 50,000 inches
6 inches = 50,000 x 6/63360
6 inches = 4.73 miles
Since 4.73 miles is not an integer, therefore we take 5 a
s an integer on number line. Now we need to make following calculations to present number line as 5 miles.
Since 6 inches = 4.73 miles
Therefore 5 miles = 6 x 5/4.73
5 miles will be represented by 6.34 inches.
We can make the graph by following steps:
First of all draw a 6.34 inches line and divide it in 5 important parts. Except one part from the left, let us give all parts a distance of 1.268 inch. Now divide the first part in 4 equal parts and each part will be equal to 0.32 inch.

Question 10.
Construct a graphical scale for scale 1 inch = 1 mile and which can be read in furlongs and miles.
Answer:
For graphical scale, to know the length of the line we need to make following calculations.
1 inch = 1 mile
Since 1 inch = 1 mile and therefore, 6 inches = 6 miles We can make the graph by following steps:
First of all draw a 6 inches line and divide it in 6 important parts. Except one part from the left, let us give all parts a distance of one 1 inch. Now divide the first part in 4 equal parts and each part will be equal to 0.25 inch.

In This Post we are  providing  CHAPTER 3 LATITUDE, LONGITUDE AND TIME NCERT MOST IMPORTANT QUESTION for Class 11 GEOGRAPHY which will be beneficial for students. These solutions are updated according to 2021-22 syllabus. These   can be really helpful in the preparation of Board exams and will provide you with a brief knowledge of the chapter.

NCERT MOST IMPORTANT QUESTION ON LATITUDE, LONGITUDE AND TIME

Question 1.
How can we determine latitude of a place?
Answer:
Latitude of a place may be determined with the help of the altitude of the sun or the Pole Star.

Question 2.
What is 1ST?
Answer:
The Indian Standard Time is calculated from 82°30’E meridian passing through Mirzapur. 1ST is plus 5.30 hours from the GMT ((82°30’ x 4) (330 minutes = 5 hours 30 minutes).

Question 3.
Which countries have more than one time zone?
Answer:
The countries with large east-west span may choose more than one standard meridian to get more than one time zone such as Russia, Canada and the United States of America.

Question 4.
When it is 12:00 noon in Greenwich then what will be the time at Thimbu, capital of Bhutan which is located at 90° east?
Answer:

At one degree time changes by 4 minutes Difference between Greenwich and Thimbu is equal to 90°
Therefore time difference = 90 x 4
= 360 minutes = 6 hours (360/60)

Question 5.
When it is 12:00 noon in Greenwich then what will be the time at New Orleans which is located at 90° west?
Answer:
At one degree time changes by 4 minutes Difference between Greenwich and New Orleans is equal to 90°
Therefore time difference = 90 x 4
= 360 minutes = 6 hours (360/60)
Since it is towards, west, time will decrease by 4 minutes on each longitude. Therefore, it will be 6 am in the morning.

Question 6.
When it is 12:00 noon in Greenwich then what will be the time at New York which is located at 74° west?
Answer:
At one degree time changes by 4 minutes Difference between Greenwich and New York is equal to 74°
Therefore time difference
= 74 x 4
= 296 minutes
= 4 hours 56 minutes (296/60)
Since it is towards, west, time will decrease by 4 minutes on each longitude.
Therefore, it will be 7:04 am in the morning.

Question 7.
What is International Date Line? What
is its importance?
Answer:
The world is divided into 24 time zones, there has to be a place where there is a difference in days, somewhere the day truly “starts” on the planet. The 180° line of longitude is approximately where the International Date Line passes. The time at this longitude is exactly 12 hours from the 0° longitude, irrespective of one travels westward or eastward from the Prime Meridian. Time decreases east of the Prime Meridian and increases to its west. Hence, for a person moving east of the Prime Meridian, the time would be 12 hours less than the time at 0° longitude. For another person moving westward, the time would be 12 hours more than the Prime Meridian. For example, a person moving eastward on Tuesday will count the day as Wednesday once [ the International Date Line is crossed.
Similarly, another person starting his journey on the same day, but moving westward will count the day as Monday after crossing the line.

Question 8.
Explain the relationship between r longitude and time,
Answer:
The earth rotates from west to east over its axis. It makes the sun rise in the east and set in the west. The rotation of
the earth over its axis takes 24 hours to complete one circle or 360° of longitudes. As 180° of longitudes fall both east and west of the Prime Meridian, the sun, thus takes 12 hours’ time to traverse the eastern and western hemispheres. In other words, the sun traverses 15° of longitudes per hour or one degree of longitude in every four minutes of time. The time decreases when we move from west to east and increases with our westward movement. The rate of the time at which the sun traverses over certain degrees of longitudes is used to determine the local time of an area with respect to the time at the Prime Meridian (0°Longitude). For example when it is 2 pm in Greenwich, it will be 3 pm in 15° east. (15×4 = 60 minutes = 1 hour).

Question 9.
Explain the process or drawing latitudes.
Answer:
Process of drawing latitudes:

• Draw a circle.
• Divide it into two equal halves by drawing a horizontal line in the centre. This represents the equator.
• Place a protractor on this circle in a way that 0° and 180° line on the protractor coincide with the equator on the paper.
• Now to draw 20°S, mark two points at an angle of 20° from the equator, east and west in the lower half of the circle.
• The arms of the angle cut the circle at two points. Join these two points by a line parallel to the equator. It will be 20°S.
  

Question 10.
Explain the process of drawing longitudes Ans. Process of drawing longitudes:
Answer:

• Draw a circle whose centre represents the North Pole. The circumference will represent the equator.
• Draw a vertical line through the centre of the circle, i.e. crossing the North Pole. This represents the 0° and 180° meridians, which meet at the North Pole as shown in figure given below:
  
• To draw a longitude, imagine that you are on the North Pole, i.e. at the centre of the circle as shown in Figure given above.
• Observe now that the relative directions of east and west would reverse in this case and east would be towards your left while west would be towards your right.
• Now, draw 45° E and W as shown in Figure given below:
  
• For this, place your protractor along the vertical line, coinciding with the 0° and 180° meridians and then measure 45° on both the sides, which will denote 45° . E meridian and 45° W meridian on your left and right, respectively.
• The diagram will represent the appearance of the earth if we look at it from directly above the North Pole.

In This Post we are  providing  CHAPTER 4 MAP PROJECTIONS NCERT MOST IMPORTANT QUESTION for Class 11 GEOGRAPHY which will be beneficial for students. These solutions are updated according to 2021-22 syllabus. These   can be really helpful in the preparation of Board exams and will provide you with a brief knowledge of the chapter.

NCERT MOST IMPORTANT QUESTION ON MAP PROJECTIONS

Question 1.
How are conical projections drawn?
Answer:
A Conical projection is drawn by wrapping a cone round the globe and the shadow of graticule network is projected
on it. When the cone is cut open, a projection is obtained on a flat sheet. A conical projection is one, which is drawn by projecting the image of the ‘ graticule of a globe on a developable cone, which touches the globe along a parallel of latitude called the standard parallel. As the cone touches the globe located along AB, the position of this parallel on the globe coinciding with that on the cone is taken as the standard parallel. The length of other parallels on either side of this parallel are distorted.

Question 2.
What is map projection?
Answer:
It is the system of transformation of the spherical surface onto a plane | surface. It is carried out by an orderly
and systematic representation of the parallels of latitude and the meridians of longitude of the spherical earth or part of it on a plane surface on a conveniently chosen scale. In map projection we try to represent a good model of any part of the earth in its true shape and dimension. But distortion in some form or the other is inevitable.

To avoid this distortion, various methods have been devised and many types of projections are drawn. Due to this reason, map projection is also defined as the study of different methods which have been tried for transferring the lines of graticule from the globe to a flat sheet of paper.

Question 3.
What are the qualities and limitations of a globe?
Answer:
Qualities of globe can be expressed as follows:

• A globe is the best model of the earth. Due to this property of the globe, the shape and sizes of the continents and oceans are accurately shown on it.
• It shows the directions and distances very accurately.
• The globe is divided into various segments by the lines of latitude and longitude.

Limitations:

• It is expensive.
• It can neither be carried everywhere easily nor can a minor detail be shown on it.
• Besides, on the globe the meridians are semi-circles and the parallels are circles. When they are transferred on a plane surface, they become intersecting straight lines or curved lines.

Question 4.
Classify the projections on the basis of method of construction.
Answer:
On the basis of method of construction, projections are generally classified into perspective, non-perspective and conventional or mathematical.

• Perspective projections: These can be drawn taking the help of a source of light by projecting the image of a network of parallels and meridians of a globe on developable surface.
• Non-perspective projections: These are developed without the help of a source of light or casting shadow on surfaces, which can be flattened.
• Mathematical or conventional projections: These are those, which are derived by mathematical computation and formulae and have little relations with the projected image.

Question 5.
Classify projections on the basis of global properties.
Answer:
On the basis of global properties, projections are classified into:

• Equal Area Projection
• Orthomorphic Projection,
• Azimuthal Projection and
• Equidistant Projections.
  • Equal Area Projection: It is also called homolographic projection. It is that projection in which areas of various parts of the earth are represented correctly.
  • Orthomorphic or True-Shape projection: It is one in which shapes of various areas are portrayed correctly. The shape is generally maintained at the cost of the correctness of area.
  • Azimuthal or True-Bearing projection: It is one on which the direction of all points from the centre is correctly represented.
  • Equidistant or True Scale projection: It is that where the distance or scale is correctly maintained.
• However, there is no such projection, which maintains the scale correctly throughout. It can be maintained correctly only along some selected parallels and meridians as per the requirement.

Question 6.
Write a short note on developable surface and zenithal projections.
Answer:
A developable surface is one, which can be flattened, and on which, a network of latitude and longitude can be projected. A cylinder, a cone and a plane have the property of developable surface. On the basis of nature of developable surface, the projections are classified as cylindrical, conical and zenithal projections.

1. Cylindrical Projections: These are made through the use of cylindrical developable surface. A paper-made cylinder covers the globe, and the parallels and meridians are projected on it.

2. Zenithal projection: It is directly obtained on a plane surface when plane touches the globe at a point and the graticule is projected on it. Generally, the plane is so placed on the globe that it touches the globe at one of the poles. These projections are further subdivided into normal, oblique or polar as per the position of the plane touching the globe.

• Normal Projection: If the developable surface touches the globe at the equator, it is called equatorial or normal projection.
• Oblique Projection: If it is tangential to a point between the pole and the equator, it is called the oblique projection;
• Polar Projection: If it is tangential to the pole, it is called the polar projection.

Question 7.
Explain the qualities of Mercator projection.
Answer:
Mercator’s Projection is very useful for navigational purposes. A Dutch cartographer Mercator Gerardus Karmer developed this projection in 1569. The projection is based on mathematical formulae.
Properties:

• It is an orthomorphic projection in which the correct shape is maintained.
• The distance between parallels increases towards the pole.
• Like cylindrical projection, the parallels and meridians intersect each other at right angle. It has the characteristics of showing correct directions.
• A straight line joining any two points on this projection gives a constant bearing, which is called a Laxodrome or Rhumb line.
• All parallels and meridians are straight lines and they intersect each other at right angles.
• All parallels have the same length which is equal to the length of equator.
• All meridians have the same length and equal spacing. But they are longer than the corresponding meridian on the globe.
• Spacing between parallels increases towards the pole.
• Scale along the equator is correct as it is equal to the length of the equator on the globe; but other parallels are longer than the corresponding parallel on the globe; hence the scale is not correct along them.
• Shape of the area is maintained, but at the higher latitudes distortion takes place.
• The shape of small countries near the equator is truly preserved while it increases towards poles.
• It is an azimuthal projection.
• This is an orthomorphic projection as scale along the meridian is equal to the scale along the parallel.

Question 6.
Explain properties, limitations and uses of cylindrical equal area projection.
Answer:
The cylindrical equal area projection is also known as the Lambert’s projection. It has been derived by projecting the surface of the globe with parallel rays on a cylinder touching it at the equator. Both the parallels and meridians are projected as straight lines intersecting one another at right angles. The pole is shown with a parallel equal to the equator; hence, the shape of the area gets highly distorted at the higher latitude.

Properties

• All parallels and meridians are straight lines intersecting each other at right angle.
• Polar parallel is also equal to the equator.
• Scale is true only along the equator.

Limitations

• Distortion increases as we move towards the pole.
• The projection is non-orthomorphic.
• Equality of area is maintained at the cost of distortion in shape.

Uses

• The projection is most suitable for the area lying between 45° N and S latitudes.
• It is suitable to show the distribution of tropical crops like rice, tea, coffee, rubber and sugarcane.

Question 7.
Explain properties of Conical Projection with one Standard Parallel.
Answer:
A conical projection is one, which is drawn by projecting the image of the graticule of a globe on a developable cone, which touches the globe along a parallel of latitude called the standard parallel. As the cone touches the globe located along AB, the position of this parallel on the globe coinciding with that on the cone is taken as the standard parallel.

Properties

• All the parallels are arcs of concentric circle and are equally spaced.
• All meridians are straight lines merging at the pole. The meridians intersect the parallels at right angles.
• The scale along all meridians is true.
• An arc of a circle represents the pole.
• The scale is true along the standard parallel but exaggerated away from the standard parallel.
• Meridians become closer to each other towards the pole.
• This projection is neither equal area nor orthomorphic.

Question 8.
Explain the limitations and uses of Conical Projection with one Standard Parallel.
Answer:
Limitations

• It is not suitable for a world map due to extreme distortions in the hemisphere opposite the one in which the standard parallel is selected.
• Even within the hemisphere, it is not suitable for representing larger areas as the distortion along the pole and near the equator is larger.

Uses

• This projection is commonly used for showing areas of mid-latitudes with limited latitudinal and larger longitudinal extent.
• A long narrow strip of land running parallel to the standard parallel and having east-west stretch is correctly shown on this projection.
• Direction along standard parallel is used to show railways, roads, narrow river valleys and international boundaries.
• This projection is suitable for showing the Canadian Pacific Railways, Trans- Siberian Railways, international boundaries between USA and Canada and the Narmada Valley.

Question 9.
Prepare graticule for a Cylindrical Equal Area Projection for the world when R.F. is 1: 300,000,000 and the interval is 15° apart.
Answer:
Construction

• Draw a circle of 2.1 cm radius;
• Mark the angles of 15°, 30°, 45°, 60°, 75° and 90° for both, northern and southern hemispheres;
• Draw a line of 13.2 cm and divide it into 24 equal parts at a distance of 0.55cm apart.
• This line represents the equator;
• Draw a line perpendicular to the equator at the point where 0° is meeting the circumference of the circle;
• Extend all the parallels equal to the length of the equator from the perpendicular line; and Complete the projection as shown in figure given below:
  

Question 10.
Draw a Mercator Projection for the world map when the R.F. is 1:250,000,000 and the interval between the latitude and longitude is 15°.
Answer:
Calculation: Radius of the reduced earth R is “1 is 1: 250,000,000 Length of the equator 2πR or

1 × 227 × 2=6.28 inches

Construction

• Draw a line of 6.28″ inches representing the equator as Equation.
• Divide it into 24 equal parts. Determine the length of each division using the following formula: Length of the equator multiplied by interval divided by 360°.
• Calculate the distance for latitude with the help of the table given below:
  Latitude Distance 15° 0.25 x 1 = 0.25″ inch 30° and so on, Complete the projection as shown in Figure given below:
  

In This Post we are  providing  CHAPTER 5 TROPGRAPHICAL MAPS NCERT MOST IMPORTANT QUESTION for Class 11 GEOGRAPHY which will be beneficial for students. These solutions are updated according to 2021-22 syllabus. These   can be really helpful in the preparation of Board exams and will provide you with a brief knowledge of the chapter.

NCERT MOST IMPORTANT QUESTION ON TROPGRAPHICAL MAPS

Question 1.
What are the features of contours?
Answer:
Some basic features of contour lines are:

• A contour line is drawn to show places of equal heights.
• Contour lines and their shapes represent the height and slope or gradient of the landform.
• Space between contour lines represents slope. Closely spaced contours represent steep slopes while widely spaced contours represent gentle slope.
• When two or more contour lines merge with each other, they represent features of vertical slopes such as cliffs or waterfalls.
• Two contours of different elevation usually do not cross each other.

Question 2.
Explain how do we interpret a topographical sheet?
Answer:
It is essential to have knowledge of map language and sense of direction are essential in reading and interpreting topo-sheets. We must first look for the northline and the scale of the map and orient ourselves accordingly. We must have a thorough knowledge of the legends / key given in the map depicting various features. All topo-sheets contain a table showing conventional signs and symbols used in the map. We must be acquainted with conventional symbols, signs and colours.

Question 3.
Under which heads is a topographical sheet interpreted? Explain each in short.
Answer:
A topographic sheet is usually interpreted under the following way:

• Marginal Information: It includes the topographical sheet number, its location, grid references, its extent in degrees and minutes, scale, the districts covered, etc.
• Relief of the Area: The general topography of the area is studied to identify different landforms along with peaks, ridges, spur and the general direction of the slope.
• Drainage of the Area: We also need to interpret the important rivers and their tributaries and the type and extent of valleys formed by them, the types of drainage pattern, i.e. dendritic, radial, ring, trellis, internal, etc.
• Land Use: It includes the use of land under different categories like Natural vegetation and forest which part of the area is forested, whether it is dense forest or thin, and the categories of the forest found there like Reserved, Protected, Classified / Unclassified.
• Transport and Communication: The means of transportation include national or state highways, districts roads, cart tracks, camel tracks, footpaths, railways, waterways, major communication lines, post offices, etc. topographical sheet presents each of these.
• Settlement: Settlements are studied under rural settlements and urban settlements.
• Occupation: The general occupation of the people of the area may be identified with the help of land use and the type of settlement.

Question 4.
What factors determine the site of settlements?
Answer:
Various factors determine the site of settlements like

• Source of water
• Provision of food
• Nature of relief
• Nature and character of occupation
• Defence.

Question 5.
Write a short note on map interpretation.
Answer:
Map interpretation involves the study of factors that explain the causal relationship among several features shown on the map. For example, the distribution of natural vegetation and cultivated land can be better understood against the background of landform and drainage. Likewise, the distribution of settlements can be examined in association with the levels of transport network system and the nature of topography.

Question 6.
Explain the steps involved in drawing, a Cross-section from their contours in different topographical landforms.
Answer:
The following steps may be followed to draw cross-sections of various relief features from their contours:

• Draw a straight line cutting across the contours on the map and mark it as XY.
• Take a strip of white paper or graph and place its edge along the XY line.
• Mark the position and value of every contour that cuts the line XY.
• Choose a suitable vertical scale, e.g. V2 cm =100 metres, to draw horizontal lines parallel to each other and equal to the length of XY. The number of such lines should be equal or more than the total contour lines.
• Label the appropriate values corresponding to the contour values along the vertical of the cross-section. The numbering may be started with the lowest value represented by the contours.
• Place the edge of the marked paper along the horizontal line at the bottom line of the cross-section in such a way that XY of the paper corresponds to the XY of the map and mark the contour points.
• Draw perpendiculars from XY line, intersecting contour lines, to the corresponding line at the cross-section base.
• Smoothly join all the points marked on different lines at the cross-section base.

Question 7 .
Under which heads are topographical maps explained?
Answer:
A topographic sheet is usually interpreted in the following way:

• Marginal Information: It includes the topographical sheet number, its location, grid references, its extent in degrees and minutes, scale, the districts covered, etc.
• Relief of the Area: The general topography of the area is studied to identify different landforms along with peaks, ridges, spur and the general direction of the slope. These features are studied under the following heads:
  • Hill: With concave, convex, steep or gentle slope and shape.
  • Plateau: Whether it is broad, narrow, flat, undulating or dissected.
  • Plain: Its types, i.e. alluvial, glacial, karst, poastal, marshy, etc.
  • Mountain: General elevation, peak, passes, etc.
• Drainage of the Area: We also need to interpret the important rivers and their tributaries and the type and extent of valleys formed by them, the types of drainage pattern, i.e. dendritic, radial, ring, trellis, internal, etc.
• Land Use: It includes the use of land under different categories like Natural vegetation and forest, which part of the area is forested, whether it is dense forest or thin, and the categories of forest found there like Reserved, Protected, Classified / Unclassified.
• Transport and Communication: The means of transportation include national or state highways, district roads, cart tracks, camel tracks, footpaths, railways, waterways, major communication lines, post offices, etc. topographical sheet presents each of these.
• Settlement: Settlements are studied under the following heads:
  • Rural Settlements: The types and patterns of rural settlements, i.e. compact, semi-compact, dispersed, linear, etc.
  • Urban Settlements: Type of urban settlements and their functions, i.e. capital cities, administrative towns, religious towns, port towns, hill stations, etc.
• Occupation: The general occupation of the people of the area may be identified with the help of land use and the type of settlement. For example, in rural areas the main occupation of majority of the people is agriculture; in tribal regions, lumbering and primitive agriculture dominates and in coastal areas, fishing is practised. Similarly, in cities and towns, services and business appear to be the major occupations of the people.

Question 8.
Explain about identification of cultural features from topographical sheets
Answer:
Settlements, buildings, roads and railways are important cultural features shown on topographical sheets through conventional signs, symbols and colours. The location and pattern of distribution of different features help in understanding the area shown on the map.
Types of Settlements: Four types of rural settlements may be identified on the map:

1. Compact
2. Scattered
3. Linear
4. Circular

Urban centres are distinguished as:

• Cross-road town
• Nodal point
• Market centre
• Hill station
• Coastal resort centre
• Port
• Manufacturing centre with suburban villages or satellite towns
• Capital town
• Religious centre

Site of settlements:
It should be closely examined with reference to the contour and drainage map. Density of settlement is directly related to food supply. Sometimes, village settlements form alignments, i.e. they are spread along a river valley, road, embankment, coastline – these are called linear settlements. In the case of an urban settlement, a cross-road town assumes a fan-shaped pattern, the houses being arranged along the roadside and the crossing being at the heart of the town and the main market place. In a nodal town, the roads radiate in all directions.

Transport and Communication Pattern:
Relief, population, size and resource development pattern of an area directly influence the means of transport and communication and their density. These are depicted through conventional signs and symbols. Means of transport and communication provide useful information about the area shown on the map.

Question 9.
Name some of the methods used to depict relief features of the earth. Which of these are most common?
Answer:
A number of methods have been used to show the relief features of the Earth’s surface on maps, over the years. These methods include hachure, hill shading,’ layer tints, benchmarks and spot heights and contours. However, contours and spot heights are predominantly used to depict the relief of an area on all topographical maps.

Question 10.
Name the slope if contours show following features:

• Contours in this type of slope are widely spaced in the lower parts and are closely spaced in the upper parts.
• The contours are widely spaced in the upper parts and are closely spaced in the lower parts.
• The contours representing this type of slope are far apart.
• The contours are closely spaced Answer:
  • Concave Slope
  • Convex Slope
  • Gentle Slope
  • Steep Slope.