Title SAMPLE PAPER(2025) -4.pdf ✅

Page 2 Sample Paper 04 CBSE Physics Class 12 6. A current-carrying loop is placed in a uniform magnetic field. The torque acting on it does not depend upon (a) area of loop (b) shape of loop (c) number of turns in loop (d) strength of current and magnetic field 7. A small piece of metal wire is dragged across the gap between the poles of a magnet in 0 4. s. If change in magnetic flux in the wire is 8 10 Wb 4 # - , then E.M.F. induced in the wire is (a) 8 10 V3 # - (b) 6 10 V3 # - (c) 4 10 V3 # - (d) 2 10 V3 # - 8. Three point charges are placed at the corners of an equilateral triangle as shown in figure. Assuming only electrostatic forces are acting, the system (a) Can never be in equilibrium. (b) Will be in equilibrium if charges rotate about the centre of the triangle. (c) Will be in equilibrium if charges have same magnitude but different signs. (d) Will be in equilibrium if charges have different magnitudes and different signs. 9. If the energy of hydrogen atom in ground state is - . eV13 6 , then its energy in the first excited state will be (a) -3 4. eV (b) -6 8. eV (c) - . eV27 2 (d) - . eV52 4 10. A circular loop of area 0 0. m1 2 carrying a current of A10 , is held perpendicular to a magnetic field of intensity 0.1 T. The torque acting on the loop is (a) zero (b) 0.01 N-m (c) 0.1 N-m (d) 0.8 N-m 11. A m2 long solenoid with radius cm2 and 2000 turns has a another solenoid of 1000 turns wound closely near its mid-point. The mutual inductance of solenoids is (a) 0 8. mH (b) 1 6. mH (c) 3 2. mH (d) 6 4. mH 12. According to the Maxwell’s displacement current law, a changing electric field is source of (a) an e.m.f. (b) magnetic field (c) pressure gradient (d) all of these Continue on n ext page.....
Page 3 Sample Paper 04 CBSE Physics Class 12 13. Assertion : A white source of light during interference forms only white and black fringes. Reason : Width of fringe is inversely proportional to the wavelength of the light used. (a) Both Assertion and Reason are correct and the Reason is a correct explanation of the Assertion. (b) Both Assertion and Reason are correct but Reason is not a correct explanation of the Assertion. (c) The Assertion is correct but Reason is incorrect. (d) Both the Assertion and Reason are incorrect. 14. Assertion : If the temperature of a semiconductor is increased then it’s resistance decreases. Reason : The energy gap between conduction band and valence band is very small. (a) Both Assertion and Reason are correct and the Reason is a correct explanation of the Assertion. (b) Both Assertion and Reason are correct but Reason is not a correct explanation of the Assertion. (c) The Assertion is correct but Reason is incorrect. (d) Both the Assertion and Reason are incorrect. 15. Assertion (A) : The electric lines of forces diverges from a positive charge and converge at a negative charge. Reason (A) : A charged particle free to move in an electric field always move along an electric line of force. (a) Both Assertion and Reason are correct and the Reason is a correct explanation of the Assertion. (b) Both Assertion and Reason are correct but Reason is not a correct explanation of the Assertion. (c) The Assertion is correct but Reason is incorrect. (d) Both the Assertion and Reason are incorrect. 16. 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. (a) Both Assertion and Reason are correct and the Reason is a correct explanation of the Assertion. (b) Both Assertion and Reason are correct but Reason is not a correct explanation of the Assertion. (c) The Assertion is correct but Reason is incorrect. (d) Both the Assertion and Reason are incorrect. SECTION-B 17. A ray of light incident on an equilateral glass prism ( ) μ g = 3 moves parallel to the base line of the prism inside. it Find the angle of incidence for this ray. 18. The motion of copper plate is damped when it is allowed to oscillate between the two poles of a magnet. What is the cause of this damping? 19. (i) Write the β -decay or tritium in symbolic form. (ii) Why is it experimentally found difficult to detect neutrinos in this process? Continue on n ext page.....