CBSE Class 12 Physics 2022

Marks by chapter

Counted from the 102 questions listed below, as the 2022 papers print them. CBSE allocates marks per unit, not per chapter — this is what was observed, not an official CBSE weightage. Every year compared →

102 questions from 2022

• Q1With the help of a circuit diagram, explain briefly how a p-n junction diode works as a half-wave rectifier.2 mk
• Q1The V - I characteristics of a solar cell is shown in the figure. What do the points P and Q represent? Give the…2 mk
• Q1What is meant by energy band gap in a solid? Draw the energy band diagrams for a conductor, an insulator and a…2 mk
• Q1Explain the formation of depletion layer and barrier potential in a p-n junction diode.2 mk
• Q1Explain the formation of depletion region in a p-n junction.2 mk
• Q1What is meant by doping of an intrinsic semiconductor? Name the two types of atoms used for doping of Ge / Si.2 mk
• Q1Two crystals C_1 and C_2, made of pure silicon, are doped with arsenic and aluminium respectively. (i) Identify the…2 mk
• Q1Give two differences between a half wave rectifier and a full wave rectifier.2 mk
• Q1Draw energy band diagrams of n-type and p-type semiconductors at temperature T > 0K, depicting the donor and acceptor…2 mk
• Q2Draw the graph showing the variation of the number (N) of scattered alpha particles with scattering angle ( θ ) in…2 mk
• Q2Draw the circuit diagram of an illuminated photodiode and its I-V charcteristics. 1 How can a photodiode be used to…2 mk
• Q2Name the device which converts an ac input signal into a dc output signal. Write the principle of working of the device.2 mk
• Q2Briefly explain the working of a light emitting diode. Mention its two uses.2 mk
• Q2(i) Distinguish between isotopes and isobars. (ii) Two nuclei have different mass numbers A_1 and A_2. Are these nuclei…2 mk
• Q2Distinguish between intrinsic and extrinsic semiconductors. Although in an extrinsic semiconductor n_e ≠ n_h, yet it is…2 mk
• Q2Name the spectral series for a hydrogen atom which lies in the visible region. Find the ratio of the maximum to the…2 mk
• Q2What results do you expect if α -particle scattering experiment is repeated using a thin sheet of hydrogen in place of…2 mk
• Q2(i) Define the terms: 'impact parameter' and 'distance of closest approach' for an α -particle in Geiger-Marsden…2 mk
• Q3Why a photo-diode is operated in reverse bias whereas current in the forward bias is much larger than that in the…2 mk
• Q3How is an emf generated by a solar cell due to the three basic processes involved? Explain.2 mk
• Q3Name the extrinsic semiconductors formed when a pure germanium is doped with (i) a trivalent and (ii) pentavalent…2 mk
• Q3Define barrier potential. Why does the thickness of the depletion layer in a p-n junction diode vary with increase in…2 mk
• Q3Explain the formation of the barrier potential in a p-n junction.2 mk
• Q3Write the characteristics of a p-n junction which make it suitable for rectification.2 mk
• Q3Name the device which converts electrical energy into light energy. Write three advantages of the device.2 mk
• Q4Define the term - Distance of closest approach. How will it be affected, for an α - particle, if kinetic energy of the…3 mk
• Q4State Bohr's postulate to explain stable orbits in a hydrogen atom. Prove that the speed with which the electron…3 mk
• Q4Draw a graph showing the variation of number of particles scattered (N) with the scattering angle θ in Geiger-Marsden…3 mk
• Q4Calculate the frequency of a photon of energy 6.5 × 10^-19 J. Can this photon cause emission of an electron from the…3 mk
• Q4Differentiate between nuclear fission and nuclear fusion. Deuterium undergoes fusion as per the reaction: _1^2 H+_1^2 H…3 mk
• Q4(i) Depict a plane electromagnetic wave propagating along the x-axis. Write the expressions for its oscillating…3 mk
• Q4How will the interference pattern in Young's double-slit experiment be affected if: (i) The screen is moved away from…3 mk
• Q5A point source in air is kept 24 cm in front of a concave spherical glass surface (_a μ_g=1.5) and radius of curvature…3 mk
• Q5Ultra-violet light of wavelength 200 nm from a source is incident on a metal surface. If the stopping potential is -2.5…3 mk
• Q5(i) Draw V-I characteristics of a p-n Junction diode. (ii) Differentiate between the threshold voltage and the…3 mk
• Q5State the conditions for total internal reflection to take place. A tank is filled with a transparent liquid to height…3 mk
• Q5An alpha particle is accelerated through a potential difference of 100 V. Calculate: (i) The speed acquired by the…3 mk
• Q5An electron in a hydrogen atom makes transitions from orbits of higher energies to orbits of lower energies. (i) When…3 mk
• Q5Monochromatic light of wavelength 600 nm is incident from air on a water surface. The refractive index of water is…3 mk
• Q5The work function of a metal is 2.31 eV. Photoelectric emission occurs when light of frequency 6.4 × 10^14 Hz is…3 mk
• Q5Answer the following, giving reason: The resistance of a p-n junction is low when it is forward biased and is high when…3 mk
• Q6Calculate the energy released in MeV in the following reaction: _1^2 H+_1^3 H →_2^4 He+n Given: m(_1^2 H)=2.014102 u…3 mk
• Q6A beam of light consisting of two wavelengths 600 nm and 500 nm is used in a Young's double slit experiment. The slit…3 mk
• Q6With the help of a ray diagram, show how a compound microscope forms a magnified image of a tiny object, at least…3 mk
• Q6Draw a labelled ray diagram showing the formation of an image by an astronomical refracting telescope in normal…3 mk
• Q6Using Huygen's principle, for a plane wavefront incident on a plane reflecting surface, draw the reflected wavefront.…3 mk
• Q6In Geiger-Marsden experiment, calculate the distance of closest approach for an alpha particle with energy 2.56 ×…3 mk
• Q6An equiconvex lens forms a two times enlarged real image when an object is kept 16 cm from it. The lens is cut into two…3 mk
• Q6Briefly explain how bright and dark fringes are formed on a screen due to the diffraction at a single slit. Hence,…3 mk
• Q7The de-Broglie wavelength associated with an electron is 0.30 nm. Calculate: the speed, and the kinetic energy (in eV),…3 mk
• Q7In a diffraction pattern due to a single slit, how will the angular width of central maximum change, if (i) Orange…3 mk
• Q7Explain with the help of a suitable diagram, the phenomenon on which an optical fibre works. Mention any two uses of…3 mk
• Q7Give an example each of a metal from which photoelectric emission takes place when irradiated by (i) UV light (ii)…3 mk
• Q7The interference pattern is not observed in Young's double slit experiment when the two sources S_1 and S_2 are far…3 mk
• Q7A ray is incident on a prism of material of refractive index √2 at point M such that it grazes along NC after emerging…3 mk
• Q7How can you differentiate whether a pattern is produced by a single slit or double slits? Derive the expression for the…3 mk
• Q7Briefly explain how bright and dark fringes are formed on the screen in Young's double slit experiment. Hence, derive…3 mk
• Q7A converging lens made of glass (μ=1 · 5) has its spherical faces of radii of curvature 10 cm and 20 cm. Find its focal…3 mk
• Q8(i) Draw a labelled ray diagram showing the formation of the image at infinity by an astronomical telescope. (ii) A…3 mk
• Q8Write two necessary conditions for total internal reflection. Two prisms ABC and DBC are arranged as shown in figure.…3 mk
• Q8(i) Define SI unit of power of a lens. (ii) A plano convex lens is made of glass of refractive index 1.5. The radius of…3 mk
• Q8A parallel beam of light of wavelength 600 nm is incident normally on a slit of width 0.2 mm. If the resulting…3 mk
• Q8In a fission event of _92^238 U by fast moving neutrons, no neutrons are emitted and final products, after the beta…3 mk
• Q8The wavelength of the waves associated with a particle having kinetic energy E is λ. How and by what factor should its…3 mk
• Q8A proton is accelerated through a potential difference V. After acceleration, the de Broglie wavelength associated with…3 mk
• Q8The energy of a hydrogen atom in the first excited state is -3.4 eV. Find: the radius of this orbit. (Take Bohr radius…3 mk
• Q8Draw the energy band diagrams for conductors, semiconductors and insulators. Which band determines the electrical…3 mk
• Q9A narrow beam of protons, each having 4.1 MeV energy is approaching a sheet of lead (Z=82). Calculate: (i) the speed of…3 mk
• Q9Use Bohr's postulate to prove that the radius of n^th orbit in a hydrogen atom is proportional to n^2. How will the…3 mk
• Q9Calculate the energy and momentum of a photon in a monochromatic beam of wavelength 331.5 nm. How fast should a…3 mk
• Q9Sketch the energy level diagram for hydrogen atom. Find the ratio of the longest and the shortest wavelength in Lyman…3 mk
• Q9Depict the variation of the potential energy of a pair of nucleons with the separation between them. Imagine the…3 mk
• Q9Use Einstein's photoelectric equation to depict the variation of the maximum kinetic energy ( E_k ) of electrons…3 mk
• Q9State Bohr's quantization condition for defining stationary orbits. Use the energy level diagram shown below to obtain…3 mk
• Q9An electron is accelerated from rest through a potential difference of 100 V. Find: (i) the wavelength associated with…3 mk
• Q9Briefly explain how emf is generated in a solar cell. Draw its I-V characteristics.3 mk
• Q9Photoelectrons are emitted from a metal surface when illuminated with UV light of wavelength 330 nm. The minimum amount…3 mk
• Q10State the working principle of an LED. Write any two important advantages and two disadvantages of LED.3 mk
• Q10Find the two possible positions of an object kept in front of a lens of +5.0 D, so that the image formed in both cases…3 mk
• Q10How is the spacing between fringes in a double slit experiment affected if: (i) the slits separation is increased, (ii)…3 mk
• Q10A ray of light passes through a prism of refractive index √2 as shown in the figure. Find: (i) The angle of incidence…3 mk
• Q10In a Young's double slit experiment using light of wavelength 600 nm, the slit separation is 0.8 mm and the screen is…3 mk
• Q10A ray of light is incident on a prism at an angle of 45° and passes symmetrically as shown in the figure. Calculate:…3 mk
• Q10Is the speed of light in glass independent of the colour of light? Give reason. A small bulb is placed at the bottom of…3 mk
• Q10James Chadwick, in 1932, studied the emission of neutral radiations when Beryllium nuclei were bombarded with alpha…3 mk
• Q10Find the ratio of the de Broglie wavelengths associated with an alpha particle and a proton, if both have the same…3 mk
• Q11The figure shows a water column BCFE surrounded by two media (1) and (3) of the same refractive index √2. A ray of…3 mk
• Q11A diver looking up through water (μ=4/3) sees the outside world contained in a circular area on the surface of water.…3 mk
• Q11The energy of hydrogen atom in an orbit is -1.51 eV. What are kinetic and potential energies of the electron in this…3 mk
• Q11Identify electromagnetic waves which: (i) are used in radar system. (ii) affect a photographic plate. (iii) are used in…3 mk
• Q11Electromagnetic waves of wavelengths λ_1, λ_2 and λ_3 are used in radar systems, in water purifiers and in remote…3 mk
• Q11The refractive index of an equilateral triangular prism kept in air is √2. Calculate: the angle of minimum deviation.…3 mk
• Q11For a glass prism of refractive index √3, the value of angle of minimum deviation δ is equal to the angle of prism A.…3 mk
• Q11With the help of a circuit diagram, explain the working of a p-n junction diode as a full-wave rectifier. Also draw its…3 mkasked 2×
• Q11An electron is in the third excited state in a hydrogen atom. It undergoes transitions to the lower energy states. What…3 mk
• Q11(i) Monochromatic light is incident on a surface separating two media. The frequency of the light after refraction…3 mk
• Q11(i) Arrange the following electromagnetic radiation in the ascending order of their frequencies: X-rays, microwaves,…3 mk
• Q12Two transparent media of refractive indices n_1 and n_2 are separated by a spherical transparent surface. The rays of…5 mk
• Q12The principle of superposition is used to understand the phenomenon of interference of light waves. The principle…5 mk
• Q12A ray of light travels from a denser to a rarer medium. After refraction, it bends away from the normal. When we keep…5 mk
• Q12A compound microscope consists of two converging lenses. One of them, of smaller aperture and smaller focal length is…5 mk
• Q12The British physicist Thomas Young explained the interference of light using the principle of superposition of waves.…5 mk