a) Promissory Note b) Acknowledgement of debt c) Conditional Promise d) None of these
2. “We have received a sum of Rs 15000/- from Sri Vikash Prasad Verma. The above amount will be repaid on demand. We have received Rs 15000/- in cash today is
a) Promissory Note b) Acknowledgement of debt c) Neither a nor b d) Both a & b
3. A cheque becomes stale after expiry of how many months from the date of the cheque?
a) 3 months b) 6 months c) 9 months d) 12 months
4. A negotiable instrument can be negotiated
a) By mere delivery if payable to bearer b) By endorsement and delivery if payable to order c) Both a and b are true d) Neither A Nor B is true
5. A Quasi Negotiable Instrument is
a) an instrument printed in the form of an NI b) has some characteristics of an NI c) none of them d) may be any of them
6. A truncated cheque is
a) a cheque cut into 2 pieces b) a cheque in a trunk c) scan of the physical cheque d) none of them
7. Bill of Exchange is defined in Sec ______ of NI Act
a) Sec 4
b) Sec 5
c) Sec 6
d) Sec 8
8. A promissory note is defined in Sec ______ of NI Act
a) Sec 4
b) Sec 5
c) Sec 6
d) Sec 8
9. Crossing of the cheque can be cancelled by
a) Drawer only along with his initial
b) Drawer only along with his full signature
c) Payee of the cheque
d) Holder in due course
10. The person who is directed to pay in a Bill of exchange or Cheque is known as __
a) Drawer
b) Drawee
c) Holder
d) Payee
Fill in the blanks
1. General crossing of a cheque requires parallel transverse lines simply, either with or without the words Account Payee
2. In a BE, the number of parties are 2
3. In India, the reasonable time for presentation to the bank in the case of cheques and drafts is 3 months from date of issue
4. Inchoate negotiable instruments means Incomplete instrument
5. Maker of a Bill of exchange or cheque is known as Drawer
6. Negotiable Instrument Act came into existence in 1881
7. Promissory note is defined in Sec 4 of NI Act
8. Full form of CTS is Cheque Truncation System
9. Negotiable instruments can be payable to Order, Bearer, Joint payees
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.
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.
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 : A pure semiconductor has negative temperature coefficient of resistance. Reason : In a semiconductor on raising the temperature, more charge carriers are released, conductance increases and resistance decreases.
Answer(a) In semiconductors, by increasing temperature, covalent bond breaks and conduction hole and electrons increase.
Q.2. Assertion : If the temperature of a semiconductor is increased then its resistance decreases. Reason : The energy gap between conduction band and valence band is very small.
Answer(a) In semiconductors the energy gap between conduction band and valence band is small (1 eV). Due to temperature rise, electron in the valence band gain thermal energy and may jumpy across the small energy gap, (to the conduction band). Thus conductivity increases and hence resistance decreases.
Q.3. Assertion : In semiconductors, thermal collisions are responsible for taking a valence electron to the conduction band. Reason : The number of conduction electrons go on increasing with time as thermal collisions continuously take place.
Answerc
Q.4. Assertion : A p-type semiconductors is a positive type crystal. Reason : A p- type semiconductor is an uncharged crystal.
Answer(d) There is no charge on P-type semiconductor, because each atom of semiconductor is itself neutral.
Q.5. Assertion : Silicon is preferred over germanium for making semiconductor devices. Reason : The energy gap in germanium is more than the energy gap in silicon.
Answer(c) Silicon is cheaper than germanium, so it is preferred over germanium. But energy gap in germanium is smaller than silicon.
Q.6. Assertion : Electron has higher mobility than hole in a semiconductor. Reason : The mass of electron is less than the mass of the hole.
Answer-a
Q.7. Assertion : The number of electrons in a p-type silicon semiconductor is less than the number of electrons in a pure silicon semiconductor at room temperature. Reason : It is due to law of mass action.
Answer-a
Q.8. Assertion : When two semi conductor of p and n type are brought in contact, they form p-n junction which act like a rectifier. Reason : A rectifier is used to convent alternating current into direct current.
Answer(b) Study of junction diode characteristics shows that the junction diode offers a low resistance path, when forward biased and high resistance path when reverse biased. This feature of the junction diode enables it to be used as a rectifier.
Q.9. Assertion : Diode lasers are used as optical sources in optical communication. Reason : Diode lasers consume less energy.
Answer(c) Statement – 1 is True, Statement- 2 is False
Q.10. Assertion : The diffusion current in a p-n junction is from the p-side to the n-side. Reason : The diffusion current in a p-n junction is greater than the drift current when the junction is in forward biased.
Answer(b) Diffusion current is due to the migration of holes and electrons into opposite regions, so it will be from p-side to n-side. Also in forward bias it will increases.
Q.11. Assertion : The drift current in a p-n junction is from the n-side to the p-side. Reason : It is due to free electrons only.
Answer-a
Q.12. Assertion : A p-n junction with reverse bias can be used as a photo-diode to measure light intensity. Reason : In a reverse bias condition the current is small but it is more sensitive to changes in incident light intensity.
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 : Density of all the nuclei is same. Reason : Radius of nucleus is directly proportional to the cube root of mass number.
Answer-a
Q.2. Assertion : Neutrons penetrate matter more readily as compared to protons. Reason : Neutrons are slightly more massive than protons.
Answer(b) Both statements are separately correct.
Q.3. Assertion : The mass number of a nucleus is always less than its atomic number. Reason : Mass number of a nucleus may be equal to its atomic number.
Answer(d) In case of hydrogen atom mass number and atomic number are equal.
Q.4. Assertion : The binding energy per nucleon, for nuclei with atomic mass number A > 100, decrease with A. Reason : The forces are weak for heavier nuclei.
Answer(c) Nuclear force is nearly same for all nucleus.
Q.5. Assertion : Radioactivity of 108 undecayed radioactive nuclei of half life of 50 days is equal to that of 1.2 × 108 number of undecayed nuclei of some other material with half life of 60 days. Reason : Radioactivity is proportional to half-life.
Answer-c
Q.6. Assertion : The ionising power of β-particle is less compared to β-particles but their penetrating power is more. Reason : The mass of β-particle is less than the mass of α- particle.
Answer(b) β-particles, being emitted with very high speed compared to α-particles, pass for very little time near the atoms of the medium. So the probability of the atoms being ionised is comparatively less. But due to this reason, their loss of energy is very slow and they can penetrate the medium through a sufficient depth.
Q.8. Assertion : ZXA undergoes 2α, 2β- particles and 2γ-rays, the daughter product is Z-2YA – 8. Reason : In α- decay the mass number decreases by 4 and atomic number decreases by 2. In β-decay the mass number remains unchanged, but atomic number increases by 1.
Answer-a
Q.9. Assertion : The heavier nuclei tend to have larger N/Z ratio because neutron does not exert electric force. Reason : Coulomb forces have longer range compared to the nuclear force.
Answer-a
Q.10. Assertion : A free neutron decays to a proton but a free proton does not decay to a neutron. This is because neutron is an uncharged particle and proton is a charged particle. Reason : Neutron has larger rest mass than the proton.
Answer-d
Q.11. Assertion : Cobalt-60 is useful in cancer therapy. Reason : Cobalt -60 is source of γ- radiations capable of killing cancerous cells.
Answer-d
Q.12. Assertion : It is not possible to use 35Cl as the fuel for fusion energy. Reason : The binding energy of 35Cl is to small.
Answer-c
Q.13. Assertion : Energy is released when heavy nuclei undergo fission or light nuclei undergo fusion. Reason : For heavy nuclei, binding energy per nucleon increases with increasing Z while for light nuclei it decreases with increasing Z.
Answer(d) We know that energy is released when heavy nuclei undergo fission or light nuclei undergo fusion. Therefore statement (1) is correct. The second statement is false because for heavy nuclei the binding energy per nucleon decreases with increasing Z and for light nuclei, B.E/nucleon increases with increasing Z.
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 : The force of repulsion between atomic nucleus and α-particle varies with distance according to inverse square law. Reason : Rutherford did α-particle scattering experiment.
Answer(b) Rutherford confirmed that the repulsive force of α- particle due to nucleus varies with distance according to inverse square law and that the positive charges are concentrated at the centre and not distributed throughout the atom.
Q.2. Assertion : According to classical theory the proposed path of an electron in Rutherford atom model will be parabolic. Reason : According to electromagnetic theory an accelerated particle continuously emits radiation.
Answer(d) According to classical electromagnetic theory, an accelerated charged particle continuously emits radiation. As electrons revolving in circular paths are constantly experiencing centripetal acceleration, hence they will be losing their energy continuously and the orbital radius will go on decreasing, form spiral and finally the electron will fall in the nucleus.
Q.3. Assertion : Bohr had to postulate that the electrons in stationary orbits around the nucleus do not radiate. Reason: According to classical physics all moving electrons radiate.
Answer(b) Bohr postulated that electrons in stationary orbits around the nucleus do not radiate. This is the one of Bohr’s postulate, According to this the moving electrons radiates only when they go from one orbit to the next lower orbit.
Q.4. Assertion : Electrons in the atom are held due to coulomb forces. Reason : The atom is stable only because the centripetal force due to Coulomb’s law is balanced by the centrifugal force.
Answer(c) According to postulates of Bohr’s atom model the electron revolves around the nucleus in fixed orbit of definite radii. As long as the electron is in a certain orbit it does not radiate any energy.
Q.5. Assertion : Hydrogen atom consists of only one electron but its emission spectrum has many lines. Reason : Only Lyman series is found in the absorption spectrum of hydrogen atom whereas in the emission spectrum, all the series are found.
Answer(b) When the atom gets appropriate energy from outside, then this electron rises to some higher energy level. Now it can return either directly to the lower energy level or come to the lowest energy level after passing through other lower energy levels hence all possible transitions take place in the source and many lines are seen in the spectrum.
Q.6. Assertion : Between any two given energy levels, the number of absorption transitions is always less than the number of emission transitions. Reason : Absorption transitions start from the lowest energy level only and may end at any higher energy level. But emission transitions may start from any higher energy level and end at any energy level below it.
Answer(a)
Q.7. Assertion : In Lyman series, the ratio of minimum and maximum wavelength is 3/4 Reason : Lyman series constitute spectral lines corresponding to transition from higher energy to ground state of hydrogen atom.
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 : In process of photoelectric emission, all emitted electrons do not have same kinetic energy. Reason : If radiation falling on photosensitive surface of a metal consists of different wavelength then energy acquired by electrons absorbing photons of different wavelengths shall be different.
Answer(b) Both statement I and II are true; but even it radiation of single wavelength is incident on photosensitive surface, electrons of different KE will be emitted.
Q.2. Assertion : Though light of a single frequency (monochromatic) is incident on a metal, the energies of emitted photoelectrons are different. Reason : The energy of electrons emitted from inside the metal surface, is lost in collision with the other atoms in the metal.
Answer(a) When a light of single frequency falls on the electrons of inner layer of metal, then this electron comes out of the metal surface after a large number of collisions with atom of it’s upper layer.
Q.3. Assertion : The photoelectrons produced by a monochromatic light beam incident on a metal surface have a spread in their kinetic energies. Reason : The work function of the metal is its characteristics property.
Answer(b) The kinetic energy of emitted photoelectrons varies from zero to a maximum value. Work function depends on metal used.
Q.4. Assertion : Photoelectric saturation current increases with the increase in frequency of incident light. Reason : Energy of incident photons increases with increase in frequency and as a result photoelectric current increases.
Answer(d) Photoelectric saturation current is independent of frequency. It only depends on intensity of light.
Q.5. Assertion : Photosensitivity of a metal is high if its work function is small. Reason : Work function = hf0 where f0 is the threshold frequency.
Answer(b) Less work function means less energy is required for ejecting out the electrons.
Q.6. Assertion : The photon behaves like a particle. Reason : If E and P are the energy and momentum of the photon, then p = E / c .
Answer-a
Q.7. Assertion : In an experiment on photoelectric effect, a photon is incident on an electron from one direction and the photoelectron is emitted almost in the opposite direction. It violate the principle of conservation of linear momentum. Reason : It does not violate the principle of conservation of linear momentum.Answerd
Q.9. Assertion : Two sources of equal intensity always emit equal number of photons in any time interval. Reason : Two sources of equal intensity may emit equal number of photons in any time interval.
Answer(d) Total number of emitted photons depends on energy of each photon. The energy of photons of two sources may be different.
Q.10. Assertion : Two photons of equal wavelength must have equal linear momentum. Reason : Two photons of equal linear momentum will have equal wavelength.
Answer(d) To photons of equal wavelength will have equal momentum (magnitude), but direction of momentum may be different.
Q.11. Assertion : The kinetic energy of photoelectrons emitted from metal surface does not depend on the intensity of incident photon. Reason : The ejection of electrons from metallic surface is not possible with frequency of incident photons below the threshold frequency.
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 : According to Huygen’s principle, no backward wave-front is possible. Reason : Amplitude of secondary wavelet is proportional to (1 + cos θ) where θ is the angle between the ray at the point of consideration and the direction of secondary wavelet.Answerb
Q.2. Assertion : Thin film such as soap bubble or a thin layer of oil on water show beautiful colours when illuminated by white light. Reason : It happens due to the interference of light reflected from upper and lower face of the thin film.Answer
Q.3. Assertion : No interference pattern is detected when two coherent sources are infinitely close to each other. Reason : The fringe width is inversely proportional to the distance between the two sources.Answera
Q.4. Assertion : It is necessary to have two waves of equal intensity to study interference pattern. Reason : There will be an effect on clarity if the waves are of unequal intensity.Answer(d) For interference, the waves may be of unequal intensities.
Q.5. Assertion : White light falls on a double slit with one slit is covered by a green filter. The bright fringes observed are of green colour. Reason : The fringes observed are coloured.Answer(c) Interference will take place in green light only
Q.6. Assertion : In YDSE, if a thin film is introduced in front of the upper slit, then the fringe pattern shifts in the downward direction. Reason : In YDSE if the slit widths are unequal, the minima will be completely dark.Answerd
Q.7. Assertion : In Young’s double slit experiment if wavelength of incident monochromatic light is just doubled, number of bright fringe on the screen will increase. Reason : Maximum number of bright fringe on the screen is inversely proportional to the wavelength of light usedAnswera
Q.8. Assertion : In YDSE number of bright fringe or dark fringe can not be unlimited Reason : In YDSE path difference between the superposing waves can not be more than the distance between the slits.Answerb
Q.9. Assertion : Interference pattern is made by using yellow light instead of red light, the fringes becomes narrower. Reason : In YDSE, fringe width is given by β=λD/dAnswera
Q.10. Assertion : Coloured spectrum is seen when we look through a muslin cloth. Reason : It is due the diffraction of white light on passing through fine slits.Answera
Q.11. Assertion : Diffraction takes place for all types of waves mechanical or non-mechanical, transverse or longitudinal. Reason : Diffraction’s effect are perceptible only if wavelength of wave is comparable to dimensions of diffracting device.Answerb
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 : Plane mirror may form real image. Reason : Plane mirror forms virtual image, if object is real.
Answer-b
Q.2. Assertion : The focal length of the convex mirror will increase, if the mirror is placed in water. Reason : The focal length of a convex mirror of radius R is equal to , f = R/2.
Answer(d) Focal length of the spherical mirror does not depend on the medium in which it placed.
Q.3. Assertion : The image formed by a concave mirror is certainly real if the object is virtual. Reason : The image formed by a concave mirror is certainly virtual if the object is real.
Answer(c) The image of real object may be real in case of concave mirror.
Q.4. Assertion : The image of an extended object placed perpendicular to the principal axis of a mirror, will be erect if the object is real but the image is virtual. Reason : The image of an extended object, placed perpendicular to the principal axis of a mirror, will be erect if the object is virtual but the image is real.
Answer-b
Q.5. Assertion : An object is placed at a distance of f from a convex mirror of focal length f its image will form at infinity. Reason : The distance of image in convex mirror can never be infinity
Answer-d
Q.6. Assertion : The image of a point object situated at the centre of hemispherical lens is also at the centre. Reason : For hemisphere Snell’s law is not valid.
Answer(c) The rays from centre of hemisphere cut at the centre after refraction – Snell’s law is valid in each case of refraction.
Q.7. Assertion: The focal length of an equiconvex lens of radius of curvature R made of material of refractive index μ = 1.5, is R. Reason : The focal length of the lens will be R/2.
Answer(c)
Q.8. Assertion : If the rays are diverging after emerging from a lens; the lens must be concave. Reason : The convex lens can give diverging rays.
Answer(d) If the rays cross focal point of convex lens, they become diverging.
Q.9. Assertion : The resolving power of a telescope is more if the diameter of the objective lens is more. Reason : Objective lens of large diameter collects more light.
Answer(a) RP α diameter of objective.
Q.10. Assertion : The optical instruments are used to increase the size of the image of the object. Reason : The optical instruments are used to increase the visual angle.
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 : Electromagnetic wave are transverse in nature. Reason : The electric and magnetic fields in electromagnetic waves are perpendicular to each other and the direction of propagation.
Answer(a) Transverse waves are those waves in which the particles of the medium oscillate perpendicular to the direction of wave propagation.
Q.2. Assertion : Electromagnetic waves interact with matter and set up oscillations. Reason : Interaction is independent of the wavelength of the electromagnetic wave.
Answer(c) Electromagnetic waves interact with matter via their electric and magnetic field which in oscillation of charges present in all matter. The detailed interaction and so the mechanism of absorption, scattering, etc. depend of the wavelength of the electromagnetic wave, and the nature of the atoms and molecules in the medium.
Q.3. Assertion : Electromagnetic waves carry energy and momentum. Reason : Electromagnetic waves can be polarised.
Answer(b) Consider a plane perpendicular to the direction of propagation of the electromagnetic wave. If electric charges are present in this plane, they will be set and sustained in motion by the electric and magnetic fields of the electromagnetic wave. The charge thus acquired energy and momentum from the wave. This illustrate the fact that an electromagnetic wave like other waves carries energy and momentum.
Answer(a) Electromagnetic waves have linear momentum as well as energy. This concludes that they can exert radiation pressure by falling beam of electromagnetic radiation on an object.
Q.5. Assertion : The electromagnetic wave is transverse in nature. Reason : Electromagnetic wave propagates parallel to the direction of electric and magnetic fields.
Answer(c) This electromagnetic wave contains sinusoidally time varying electric and magnetic field which act perpendicular to each other as well as at right angle to the direction of propagation of waves, so electromagnetic waves are transverse in nature. Electromagnetic wave propagate in the perpendicular direction to both fields.
Q.6. Assertion : The velocity of electromagnetic waves depends on electric and magnetic properties of the medium. Reason : Velocity of electromagnetic waves in free space is constant.
Answer(b)
Q.7. Assertion : The basic difference between various types of electromagnetic waves lies in their wavelength or frequencies. Reason : Electromagnetic waves travel through vacuum with the same speed.
Answer(a) The basic difference between various types of electromagnetic waves lies in their wavelengths or frequencies since all of them travel through vacuum with the same speed. Consequently, the waves differ considerably in their mode of interaction with matter.
Q.8. Assertion : Microwaves are better carrier of signals than optical waves. Reason : Microwaves move faster than optical waves.
Answer(d) The optical waves used in optical fibre communication are better carrier of signals than microwaves. The speed of microwave and optical wave is the same in vacuum.
Q.9. Assertion : Infrared radiation plays an important role in maintaining the average temperature of earth. Reason : Infrared radiations are sometimes referred to as heat waves
Answer(b) Infrared radiation help to maintain the earth warmth through the greenhouse effect. Incoming visible light which passes relatively easily through the atmosphere is absorbed by the earth’s surface and re-radiated as infrared radiation. The radiation is trapped by greenhouse gases such as carbon dioxide and water vapour and they heat up and heat their surroundings
