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P.S.E.B Sample Paper for 2025-
Time : 3 Hours Class 12TH^ Subject: Physics Max Marks: 70
Question number 1 contains 20 parts of one marks each. Question number 2 to 8 are of two marks each. Question number 9 to 15 are of three marks each. Question number 16 (Comprehension) is of five marks. Question number 17 and 18 are of five marks each with internal choice. All questions are compulsory.
- One mark questions: (i) Electric field intensity due to an electric dipole of very small length at a point on axial line at a distance r from its center varies as: (a) r (b) r⡰ (c) r⡹⡰ (d)r⡹⡱
(ii) The electric potential inside a conducting sphere is: (a) Zero (b) Increases from centre to the surface of the sphere. (c) Decreases from centre to the surface of the sphere. (d)Remains constant from centre to the surface of the sphere.
(iii) The electrical resistance of metals: (a) Increases with increase in temperature. (b) Is independent of temperature. (c) Decreases with increase in temperature. (d)None of the above.
(iv) The effect of temperature of the conductor on the drift velocity of electrons. (a) varies linearly with temperature b) does not depend on the temperature c) increases with increasing temperature
d) decreases with increasing temperature
(v) Path of charged particle entering in uniform magnetic field at an angle 60 ⡨is :
(a) Straight line. (b) Helical. (c) Parabola. (d)Circular.
(vi) Lenz’s law gives: (a) The magnitude of induced emf. (b) Magnitude of induced current. (c) The direction of induced emf. (d)Both the magnitude and direction of induced emf.
(vii) What is the angle between reflected ray and refracted ray when angle of incidence is equal to angle of polarization? (a) 90 ⡨ (b) 0 ⡨ (c) 30 ⡨ (d) 120 ⡨
(viii) What will happen, if the electron revolving around nucleus of an atom becomes stationary? (a) Will move away from nucleus. (b) Will falls into nucleus. (c) Nothing will happen. (d)None of the above.
(ix) What is the name given to the type of electromagnetic waves used to capture photographs of earth in foggy conditions : (a) Visible rays. (b) UV rays. (c) Microwaves. (d)Infrared rays.
(x) Which mirror is used as shaving mirror? (a) Concave mirror. (b) Convex mirror.
(xvii) Photoelectric effect is not possible for the light of all frequencies. (xviii) AC generator is based upon principle of electromagnetic induction. (xix) Power of a thick lens is smaller than the thin lens. (xx) Sustained interference is caused by the superposition of two waves coming from two coherent sources.
Two marks questions:
- What do you mean by quantization of charge? OR What is the Coulomb’s force between two small charged spheres having charge of 2 × 10⡹⡵^ C and 3 × 10⡹⡵^ ᠩ ᡨᡤᡓᡕᡗᡖ 30 ᡕᡥ ᡓᡨᡓᡰᡲ ᡡᡦ ᡓᡡᡰ.
- Define Kirchhoff’s first and second law. OR A wire of length 15 m and uniform area of cross section 6× 10 ⡹⡵ᡥ⡰has resistance of 5 Ω. Find the value of resistivity of the material of the wire.
- Draw labelled diagram of converting a galvanometer into an ammeter.
- State Faraday’s law of electromagnetic induction.
- Give any two uses of X Rays.
- Write Einstein’s photo electric equation. OR
Calculate de Broglie wavelength of electron moving with speed of 6 × 10⡳ᡥᡱ⡹⡩.
- Write any two difference between nuclear fission and nuclear fusion.
Three marks question.
- What is an equipotential surface? Show that no work is done in moving a given charge over an equipotential surface.
- With a circuit diagram, explain how a meter bridge can be used to determine unknown resistance of a given wire.
- Derive an expression for force per unit length between two parallel straight conductors carrying current in same direction. OR A solenoid of length 0.5 m has radius of 1 cm and is made up of 500 turns. It carries a current of 5 A. What is the magnitude of magnetic field inside the solenoid?
- What do you mean by impedance of LCR series circuit? Derive an expression for it by using phasor diagram. OR Find the coefficient of mutual inductance of a pair of a coil if a current of 3 A in one coil causes the flux in the second coil of 1000 turns to change by 10 ⡹⡲weber in each turn.
- What is total internal reflection? Write necessary conditions for it. OR The distance of object needle is 45 cm from a lens which forms an image on the screen placed 90 cm on the other side. What is the type of lens? What is the focal length and the size of the image if the size of object needle is 5 cm?
- Define binding energy per nucleon. Draw and explain the curve between binding energy per nucleon and mass number.
- With help of a circuit diagram, explain V-I characteristics of a PN junction diode in forward biasing.
- Read the passage carefully and answer the questions from (a) to (e).
Five marks question:
- State Gauss’s theorem. Using this theorem, derive electric field intensity due to thin uniformly charged infinite plane sheet. (1,4) OR Define capacitance. Derive capacitance of a parallel plate capacitor having dielectric slab between its plates.(1,4)
- With help of labelled diagram, write principle of astronomical telescope and derive expression for magnifying power of an astronomical telescope, when final image is formed at least distance of distinct vision. (1,1,3)
OR
What is interference of light? Derive an expression for the fringe width in the Young’s double slit experiment. (1,4)
