Class 12th Physics Investigatory Projects | CBSE
By NCERT Official
Class 12th Physics Investigatory project By NCERT Official
LIST OF INVESTIGATORY PROJECTS BY CBSE
1.To study various factors on which the internal resistance/EMF of a cell depends.
5. To investigate the dependence of the angle of deviation on the angle of incidence
using a hollow prism filled one by one, with different transparent fluids.
6. To estimate the charge induced on each one of the two identical Styrofoam (or pith)
balls suspended in a vertical plane by making use of Coulomb’s law.
CBSE Class 10th Practical | Lab Manual with experimental data | For CBSE Practical Exams Class 10
LIST OF EXPERIMENTS
1. A. Finding the pH of the following samples by using pH paper/universal indicator: Unit-I
a) Dilute Hydrochloric Acid
b) Dilute NaOH solution
c) Dilute Ethanoic Acid solution
d) Lemon juice
e) Water
f) Dilute Hydrogen Carbonate solution
B. Studying the properties of acids and bases (HCl & NaOH) on the basis of their reaction with: Unit-I
a) Litmus solution (Blue/Red)
b) Zinc metal
c) Solid sodium carbonate
2. Performing and observing the following reactions and classifying them into: Unit-I
a) Combination reaction
b) Decomposition reaction
c) Displacement reaction
d) Double displacement reaction
Action of water on quicklime
Action of heat on ferrous sulphate crystals
Iron nails kept in copper sulphate solution
Reaction between sodium sulphate and barium chloride solutions
3. Observing the action of Zn, Fe, Cu and Al metals on the following salt solutions:
Unit-I
a) ZnSO4 (aq)
b) FeSO4 (aq)
c) CuSO4 (aq)
d) Al2 (SO4)3 (aq)
Arranging Zn, Fe, Cu and Al (metals) in the decreasing order of reactivity
based on theabove result.
4. Studying the dependence of potential difference (V) across a resistor on the current (I) passing through it and determine its resistance. Also plotting a graph between V and I. Unit-IV
5. Determination of the equivalent resistance of two resistors when connected in series and parallel. Unit-IV
6. Preparing a temporary mount of a leaf peel to show stomata. Unit- II
7. Experimentally show that carbon dioxide is given out during respiration. Unit-II
8. Study of the following properties of acetic acid (ethanoic acid): Unit- I
a) Odour
b) solubility in water
c) effect on litmus
d) reaction with Sodium Hydrogen Carbonate
9. Study of the comparative cleaning capacity of a sample of soap in soft and hard
water. Unit- I
10. Determination of the focal length of: Unit-III
a) Concave mirror
b) Convex lens by obtaining the image of a distant object.
11. Tracing the path of a ray of light passing through a rectangular glass slab for different angles of incidence. Measure the angle of incidence, angle of refraction, angle of emergence andinterpret the result. Unit – III
12. Studying (a) binary fission in Amoeba, and (b) budding in yeast and Hydra with the help of prepared slides. Unit-II
13. Tracing the path of the rays of light through a glass prism. Unit-III
14. Identification of the different parts of an embryo of a dicot seed (pea, gram or red kidney bean)
15. Burning of Magnesium Ribbon
16. To show experimentally that light is necessary for photosynthesis.
Class 10th NCERT Science All Activity & Comptency Bases Questions | Important Topics
In Class 10th NCERT Science, the emphasis on activity-based learning and competency-based questions is paramount for holistic understanding and application of scientific concepts. These methodologies not only enhance theoretical knowledge but also foster practical skills and critical thinking among students.
Important topics under this approach include:
- Practical Experiments: Covering experiments related to physics, chemistry, and biology, allowing students to observe phenomena firsthand and understand underlying principles.
- Application-based Questions: These questions require students to apply theoretical knowledge to real-life scenarios, promoting analytical thinking and problem-solving skills.
- Conceptual Understanding: Topics like electricity, magnetism, chemical reactions, and biological processes are explored through activities that aid in deepening conceptual understanding.
- Skill Development: Activities focusing on laboratory techniques, data interpretation, and scientific reasoning help in developing practical skills essential for further studies and careers in science.
By incorporating these activity and competency-based questions, Class 10th NCERT Science curriculum aims to nurture a generation of scientifically literate individuals capable of tackling challenges with confidence and ingenuity.
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Class 10th Science Mind Maps
NCERT Class 10th Science Mind Maps distill intricate scientific concepts into accessible visual representations. Central themes like physics, chemistry, and biology branch into detailed nodes, clarifying relationships. Employing vibrant colors and concise labels, they facilitate comprehensive understanding, aiding students in grasping fundamental principles and fostering exam readiness.
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NCERT Class 10th Mind Maps
NCERT Class 10th Mind Maps are innovative visual tools aiding comprehension. Central themes anchor branches, elucidating complex topics into digestible nodes. Each node embodies key concepts, interconnected for holistic understanding. Utilizing colors, keywords, and hierarchies, they foster interactive learning, aiding memory retention and exam preparation.
- Class 10th Maths Mind Map
- Class 10th Science Mind Map
- Class 10th SST Mind Maps
Chemical reaction and equation Case based question Class 10
Q1. A solution of slaked lime produced by the reaction is used for white washing walls. Calcium hydroxide reacts slowly with the carbon dioxide in air to form a thin layer of calcium carbonate on the walls. Calcium carbonate is formed after two to three days of white washing and gives a shiny finish to the walls. It is interesting to note that the chemical formula for marble is also CaCO3.
On the basis of above paragraph answer the following questions:
1.) Give the reaction for the formation of calcium carbonate with physical states.
Ca(OH)2(s) + CO2(g) → CaCO3(s)↓ + H2O(l)
2.) Write the formulas of slaked lime, quick lime.
Slaked lime: Calcium hydroxide is called as slaked lime with a formula of : Ca(OH)2 ,whereas calcium oxide is called as quick lime with a formula of : Ca0.
3.) Explain why calcium carbonate is used for white washing and not any other substance.
Calcium carbonate is used for whitewashing as it produces a shiny film whilst the production of carbon dioxide and act as hard coating for the walls.
4.) Explain the importance of writing the physical states in a chemical equation.
In any chemical reaction, physical states mention the nature of the reaction and their practical aspects which are necessary for lab uses.Physical states also explains whether reaction is exothermic or endothermic.
5.) Write any one application of calcium carbonate other than white washing.
Calcium carbonate is also used in the production of antacids and can also be used to increase the levels of calcium in body.
Q2. You must have observed that iron articles are shiny when new, but get coated with a reddish brown powder when left for some time. This process is commonly known as rusting of iron. Some other metals also get tarnished in this manner. Have you noticed the colour of the coating formed on copper and silver? When a metal is attacked by substances around it such as moisture, acids, etc., it is said to corrode and this process is called corrosion. The black coating on silver and the green coating on copper are other examples of corrosion.
On the basis of above paragraph answer the following questions:
1.) Explain one benefit of corrosion.
Ans. Corrosion occurring in red blood cells of iron makes the colour of cells red which is highly useful in transportation of oxygen.
2.) Write the formula of corrosion of iron.
Ans. The general formula of corrosion of iron is Fe2 O3.
3.) If corrosion occurs in the case of iron articles, why is the iron pillar at Qutub Minar not effected?
Ans. The iron pillar at Qutub Minar is an ancient piece of metal knowledge in which the metal is very very pure( wrought iron) with low sulphur content and high phosphorus making it resistive to the outer environment.
4.) Write any two ways to prevent rusting.
Ans. The two ways to prevent rusting are:
A) Galvanization.
B) Painting of iron articles.
5.) What doe you mean by galvanization?
Ans. Galvanization is the process of applying a protective layer of Zn coating on materials which are prone to rust making it resistive and long lasting.
Q3.We have seen that the decomposition reactions require energy either in the form of heat, light or electricity for breaking down the reactants. Reactions in which energy is absorbed are known as endothermic reactions.
1.) Write the definition of exothermic reaction.
Ans. Reactions in which heat is evolved during the process are called as exothermic reactions, such as mixing of calcium oxide with water.
2.) What do you mean endothermic reactions?
Ans. Reactions in which heat is trapped or absorbed are called as endothermic reactions, such as glucose mixed with water.
3.) Write a reaction which falls under endothermic reaction.
Ans. Melting of ice, evaporation are considered under endothermic reactions. A chemical equation for these types of reaction is:
N2 + O2 + heat → 2 NO
4.) What is decomposition reaction?
Ans. Reactions in which a substance or reactant fragments to give one or many products.
5.) Explain photolysis.
Ans. Reactions in which reactant id decomposed with the help os sunlight are called as photolytic decomposition.
Ex: 2AgCl + sunlight → 2Ag + Cl2
Q4.Oxidation is the process of gaining of oxygen, or losing of hydrogen. Reduction is the process of losing of oxygen or gaining of hydrogen. The substance which undergoes oxidation is the reducing agent while the substance which undergoes reduction is known as the oxidising agent. Oxidation and reduction always take place together and these type of reactions are known as redox reactions. Some of the examples of redox reactions are given below:
(i) Give two examples of oxidation reaction from your everyday life.
Answer: Corrosion and Rancidity
(ii) Write the oxidising agent in the reaction III and VI.
Answer: CuSO4 in (III) and CuO in (VI)
(iii) Which of the following is an oxidising agent?
(a) LiAlH4
(b) Alkaline KMnO4
(c) Acidified K2Cr2O7
(d) Both (b) and (c)
Answer: d
(iv) Out of oxidation and reduction, which reaction takes place at anode?
Answer: Oxidation takes place at anode.
Q5. A chemical reaction is a representation of chemical change in terms of symbols and formulae of reactants and products. There are various types of chemical reactions like combination, decomposition, displacement, double displacement, oxidation and reduction reactions. Reactions in which heat is released along with the formation of products are called exothermic chemical reactions. All combustion reactions are exothermic reactions.
(i) The chemical reaction in which a single substance breaks down into two or more simpler substances upon heating is known as
(a) thermal decomposition reaction
(b) photo decomposition reaction
(c) electric decomposition reaction
(d) both (a) and (c)
Answer: (a) The chemical reaction in which a single substance breaks down into two or more simpler substances upon heating is known as thermal decomposition reaction.
(ii) The massive force that pushes the rocket forward through space is generated due to the
(a) combination reaction
(b) decomposition reaction
(c) displacement reaction
(d) double displacement reaction
Answer: (b) The massive force that pushes the rocket forward through space is generated due to the decomposition reaction. Hydrogen peroxide decomposes and provides it with a considerable reaction force thrust.
(iii) A white salt on heating decomposes to give brown fumes and yellow residue is left behind. The yellow residue left is of
(a) lead nitrate
(b) nitrogen oxide
(c) lead oxide
(d) oxygen gas
Answer: (c) Lead nitrate decomposes to give brown fumes of nitrogen dioxide gas and yellow residue of lead oxide is left behind.
(iv) Which of the following reactions represents a combination reaction?
(a) CaO (s) + H2O (l) → Ca(OH)2 (aq)
(b) CaCO3 (s) → CaO (s) + CO2(g)
(c) Zn(s) + CuSO4 (aq) → ZnSO4 (aq) + Cu(s)
(d) 2FeSO4(s) → Fe2O3 (s) +SO2(g) + SO3(g)
Answer: (a) A reaction in which two or more reactants combine to form a single product is known as a combination reaction.
(v) Complete the following statements by choosing correct type of reaction for X and Y.
Statement 1: The heating of lead nitrate is an example of ‘X’ reaction.
Statement 2: The burning of magnesium is an example of ‘Y’ reaction.
(a) X- Combination, Y- Decomposition
(b) X- Decomposition, Y-Combination
(c) X- Combination, Y-Displacement
(d) X- Displacement, Y-Decomposition
Answer: (b) Heating of lead nitrate to form nitrogen dioxide and lead oxide is an example of thermal decomposition reaction and the burning of magnesium ribbon in the air to form magnesium oxide is an example of combination reaction.
Chapter 7 Alternating Current Chapter assertation & reasoning Questions class 12th physics
Assertion-Reasoning Based MCQ
Code
- Both assertion and reason are true and reason is the correct explanation of assertion.
- Both assertion and reason are true but reason is not the correct explanation of assertion.
- Assertion is true but reason is false.
- Assertion is false but reason is true.
1. Assertion AC is more dangerous in use than DC
Reason It is because the peak value of AC is greater than indicated value
2. Assertion Average value of AC over a complete cycle is always zero
Reason average value of AC is always defined over half cycle
3. Assertion The alternating current lags behind the EMF by a phase angle of when AC flows through and inductor
Reason The inductive reactance increases as the frequency of AC source decreases
4. Assertion Capacitor serves as a block for DC and offers an easy path to AC
Reason Capacitive reactance is inversely proportional to frequency
5. Assertion In series LCR resonant circuit the impedance is equal to the ohmic resistance
Reason At resonance the inductive reactance exceeds the capacitive reactance
6. Assertion An alternating current shows magnetic effect
Reason Alternating current varies with time
7. Assertion In series LCR circuit resonance can take place
Reason Resonance takes place in inductance and capacitive reactance are equal and opposite
8. Assertion Power factor correction is must in heavy machinery
Reason A low power factor implies larger power loss in transmission
9. Assertion Choke coil is preferred over a registered to adjust current in an AC circuit
Reason Power factor for inductance is zero
10. Assertion When AC circuit containing resistor only its power is minimum
Reason Power of a circuit is independent of phase angle
11. Assertion A transformer cannot work on DC supply
Reason DC change is neither in magnitude nor in direction
12. Assertion A laminated core is used in transformer to increase eddy currents
Reason The efficiency of a transformer increases with increase in eddy currents
13. Assertion Soft iron is used as a core of transformer
Reason Area of hysteresis loop for soft iron is small
14. Assertion An AC generator is based on the phenomenon of electromagnetic induction
Reason In single coil we consider self induction only
Assertion-Reasoning Based MCQ Answers
1. (1)
AC is more dangerous in use than DC. It is because the peak value of AC is greater than the indicated value.
2. (2)
The mean or average value of alternating current or EMF during half cycle is given by
Im = 0.636 Io
Em = 0.6363 Eo
During the next half cycle, the mean value of AC will be equal in magnitude but opposite in direction. For this reason the average value of AC over a complete cycle is always zero. So the average value is always defined over a half cycle of AC.
3. (3)
When AC flows through an inductor current lags behind the EMF, by phase of π/2 inductive reactance
XL = ωL = 2πfL
So, when frequency increases correspondingly inductive reactance also increases.
4. (1)
The capacitive reactance of capacitor is given by
XC = 1/ ωC = 1/2πfC
So this is infinite for DC and has a very small value for AC. Hence, a capacitor blocks DC.
5. (3)
In series resonance circuit inductive reactance is equal to capacitive reactance.
ωL = 1/ωC
6. (2)
Like direct current, an AC also produces magnetic field. But the magnitude and direction of the field goes on changing continuously with time.
7. (1)
At resonant frequency,
XL = XC, Z = R (minimum)
8. (2)
A heavy machinery requires a large power.
The average power is given by,
Pav = ErmsIrmscosΦ
The required power can be supplied to the heavy machinery either by supplying larger current or by improving power factor. The first method is costly. Hence, the second one is used.
9. (1)
We can use a capacitor of suitable capacitance as a choke coil, because average power consumed per cycle in an ideal capacitor is zero. Therefore, like a choke coil a condenser can reduce AC without power dissipation.
10. (4)
The power of an AC circuit is given by,
P = EIcosΦ
Where cosΦ is a power factor and is Φ phase angle. In case of circuit containing resistance only, phase angle is zero and power factor is equal to 1. Therefore power is maximum in case of circuit containing resistor only.
11. (1)
Transformer works on AC only AC changes in magnitude as well as in direction and induced EMF.
12. (4)
Large eddy currents are produced in non laminated iron core of the transformer by induced EMF, as the resistance of bulk iron core is very small. By using thin iron sheets are score the resistance is increased. Laminating the core substantially reduces the eddy currents. Eddy currents heat up the core of the transformer. More the eddy current greater the loss of energy and efficiency goes down.
13. (1)
Hysteresis loss in the core of transformer is directly proportional to the hysteresis loop area of the core material. Since soft iron has narrow hysteresis loop area, that is why soft iron core is used in transformer.
14. (2)
According to electromagnetic induction, whenever the magnetic flux changes and EMF will be induced in the coil.
Chapter 6 Electromagnetic Induction assertation & reasoning Questions class 12th physics
Directions: These questions consist of two statements, each printed as Assertion and Reason. While answering these questions, you are required to choose any one of the following four responses.
(a) If both Assertion and Reason are correct and the Reason is a correct explanation of the Assertion.
(b) If both Assertion and Reason are correct but Reason is not a correct explanation of the Assertion.
(c) If the Assertion is correct but Reason is incorrect.
(d) If both the Assertion and Reason are incorrect.
Q.1. Assertion : Induced emf will always occur whenever there is change in magnetic flux.
Reason : Current always induces whenever there is change in magnetic flux.
Answer(c) Emf will always induces whenever, there is change in magnetic flux. The current will induced only in closed loop.
Q.2. Assertion : Faraday’s laws are consequence of conservation of energy.
Reason : In a purely resistive ac circuit, the current legs behind the emf in phase.
Answer(c) In purely resistive circuit, the current and emf are in the same phase.
Q.3. Assertion : Only a change in magnetic flux will maintain an induced current in the coil.
Reason : The presence of large magnetic flux through a coil maintain a current in the coil of the circuit is continuous.
Answer(c)
Q.4. Assertion : Lenz’s law violates the principle of conservation of energy.
Reason : Induced emf always opposes the change in magnetic flux responsible for its production.
Answer(a) Lenz’s law (that the direction of induced emf is always such as to oppose the change that cause it) is direct consequence of the law of conservation of energy.
Q.5. Assertion : An induced current has a direction such that the magnetic field due to the current opposes the change in the magnetic flux that induces the current.
Reason : Above statement is in accordance with conservation of energy.
Answer(b)
Q.6. Assertion : Acceleration of a magnet falling through a long solenoid decreases.
Reason : The induced current produced in a circuit always flow in such direction that it opposes the change to the cause that produced it.
Answer(a)
Q.7. Assertion : Figure shows a horizontal solenoid connected to a battery and a switch. A copper ring is placed on a smooth surface, the axis of the ring being horizontal. As the switch is closed, the ring will move away from the solenoid.
Reason : Induced emf in the ring, e=-dΦ/dt
Answer(a)When switch is closed , the magnetic flux through the ring will increase and so ring will move away form the solenoid so as to compensate this flux. This is according to Lenz’s law.
Q.8. Assertion : An emf can be induced by moving a conductor in a magnetic field.
Reason : An emf can be induced by changing the magnetic field.
Answer(b) In both the cases, the magnetic flux will change, and so there is an induced current.
Q.9. Assertion : Figure shows a metallic conductor moving in magnetic field. The induced emf across its ends is zero.
Reason : The induced emf across the ends of a conductor is given by e = Bvℓ sinθ.
Answer(a)
Q.10. Assertion : Eddy currents are produced in any metallic conductor when magnetic flux is changed around it.
Reason : Electric potential determines the flow of charge.
Answer(b) Both the statements are independently correct.
Q.11. Assertion : An induced emf appears in any coil in which the current is changing.
Reason : Self induction phenomenon obeys Faraday’s law of induction.
Answer(b)
Q.12. Assertion : When number of turns in a coil is doubled, coefficient of self-inductance of the coil becomes 4 times.
Reason : This is because L α N2.
Answer(b)
Chapter 5 Magnetism And Matter assertation & reasoning Questions class 12th physics
Assertion-Reasoning Based MCQ
Code
- If both assertion and reason are true and reason is the correct explanation of assertion.
- If both assertion and reason are true, but reason is not the correct explanation of assertion.
- If the assertion is true, but the reason is false.
- If the assertion is false, but the reason is true.
1 . Assertion When a magnetic dipole is placed in a non uniform magnetic field, only a torque acts on the dipole.
Reason Force wouldn’t act on dipole if magnetic field were uniform.
2. Assertion Magnetic moment of helium atom is zero.
Reason All the electron are paired in helium atom orbitals.
3. Assertion Gauss theorem is not applicable in magnetism.
Reason Mono magnetic poles do not exist.
4. Assertion The true geographic north direction is found by using a compass needle.
Reason The magnetic meridian of the earth is along the axis of rotation of the earth.
5. Assertion In the northern hemisphere the north pole of the dip needle dips downwards.
Reason The north pole of earth is as a bar magnet lies in the northern hemisphere.
6. Assertion If a compass needle be kept at magnetic north pole of the earth, the compass needle mat stay in any direction.
Reason Dip needle will stay vertical at the north pole of earth.
7. Assertion To protect any instrument from external magnetic field, it is put inside an iron box.
Reason Iron is a magnetic substance.
Assertion-Reasoning Based MCQ Answers
1 . (4)
In a non uniform magnetic field, both a torque and a net force acts on the dipole. If magnetic field were uniform, net force on dipole would be zero.
2. (1)
Helium atom has paired electrons so their electron spin are opposite to each other and hence its net magnetic moment is zero.
3. (1)
The magnetic flux through any closed surface is zero.
4. (4)
The compass needle enables us to locate magnetic north pole. If magnetic declination at that particular place is known, then true geographic north-south direction can be located. Magnetic meridian is the vertical plane passing through magnetic axis. Magnetic axis is inclined at a certain angle θ to geographical axis and earth rotates about geographic axis.
5. (3)
In the northern hemisphere, magnetic needle comes to rest along north-south direction. So, that a greater dip angle is expected in northern hemisphere.
6. (2)
At magnetic poles of the earth, the only vertical component of the earth’s field acts, horizontal component is zero. A compass needle is free to rotate in horizontal plane and is affected by horizontal component only. Thus there will be no effect on the magnetic field on the compass needle. So the needle may stop in any direction. The angle of dip at the magnetic north pole is 90° and therefore the dip needle will become vertical.
7. (2)
Iron is ferromagnetic in nature. Lines of force due to external magnetic field prefer to pass through iron.
Directions: These questions consist of two statements, each printed as Assertion and Reason. While answering these questions, you are required to choose any one of the following four responses.
(a) If both Assertion and Reason are correct and the Reason is a correct explanation of the Assertion.
(b) If both Assertion and Reason are correct but Reason is not a correct explanation of the Assertion.
(c) If the Assertion is correct but Reason is incorrect.
(d) If both the Assertion and Reason are incorrect.
Q.1. Assertion : We cannot think of a magnetic field configuration with three poles
Reason : A bar magnet does exert a torque on itself due to its own field.
Answer-d
Q.2. Assertion : In high latitudes one sees colourful curtains of light hanging down from high altitudes
Reason : The high energy charged particles from the sun are deflected to polar regions by the magnetic field of the earth.
Answera
Q.3. Assertion : The true geographic north direction is found by using a compass needle.
Reason : The magnetic meridian of the earth is along the axis of rotation of the earth.
Answer-d
Q.4. Assertion : A disc-shaped magnet is deviated above a superconducting material that has been
cooled by liquid nitrogen.
Reason : Superconductors repel a magnet.
Answer-a
Q.5. Assertion : Magnetic Resonance Imaging (MRI) is a useful diagnostic tool for producing
images of various parts of human body.
Reason : Protons of various tissues of the human body play a role in MRI.
Answer-a
Q.6. Assertion : Diamagnetic materials can exhibit magnetism.
Reason : Diamagnetic materials have permanent magnetic dipole moment.
Answer-c
Q.7. Assertion : Ferro-magnetic substances become paramagnetic above Curie temp.
Reason : Domains are destroyed at high temperature.
Answer-a
Q.8. Assertion : If a compass needle be kept at magnetic north pole of the earth the compass
needle may stay in any direction.
Reason : Dip needle will stay vertical at the north pole of earth
Answer-b
Q.9. Assertion : The ferromagnetic substance do not obey Curie’s law.
Reason : At Curie point a ferromagnetic substance start behaving as a paramagnetic substance.
Answer-b
Q.10. Assertion : The ferromagnetic substance do not obey Curie’s law.
Reason : At Curie point a ferromagnetic substance start behaving as a paramagnetic substance.
Answer-c
Q.11. Assertion : A paramagnetic sample display greater magnetisation (for the same magnetic
field) when cooled.
Reason : The magnetisation does not depend on temperature.
Answer-d
Q.12. Assertion : Electromagnetic are made of soft iron.
Reason : Coercivity of soft iron is small.
Answer-b
Q.13. Assertion : The sensitivity of a moving coil galvanometer is increased by placing a suitable magnetic material as a core inside the coil.
Reason : Soft iron has high magnetic permeability and cannot be easily magnetized or demagnetized.
Answer-c
Q.14. Assertion : The poles of magnet can not be separated by breaking into two pieces.
Reason : The magnetic moment will be reduced to half when a magnet is broken into two equal pieces.
Answer-b