Physics Sample Paper Class XII
Set - 1

 1. What is the work done in moving a charge of 10 nC between two points on an equipotential surface ? (1 mark)

 2. Name the device used for measuring the internal resistance of a secondary cell ? (1 mark)

 3. What is the nature of magnetic field in a moving coil galvanometer ? (1 mark)

 4. If a rate of change of current of 2 A/s induces an e.m.f.of 10mV in a solenoid, what is the self -inductance of the solenoid ? (1 mark)

 5. What type of magnetic material is used in making permanent magnets ? (1 mark)

 6. Two metals A, B have work-functions 2eV, 4eV respectively. Which metal has lower threshold wavelength for photoelectric effect ? (1 mark)

 7. Which have greater ionising power : alpha particles or beta particles ? (1 mark)

 8. Which part of the electromagnetic spectrum is used in operating a RADAR ? (1 mark)

 9. Which type of biasing gives a semiconductor diode very high resistance ? (1 mark)

 10. How is the luminosity of a star related to its radius ? (1 mark)

 11. An electric dipole, when held at 300 with respect to a uniform electric field of 10⁴N/C, experiences a torque of 9 x 10^-26Nm. Calculate the dipole moment of the dipole. (2 marks)

 12. A set of n identical resistors, each of resistance R ohm, when connected in series have an effective resistance X ohm and when the resistors are connected in parellel, their effective resistance is Y ohm. Find the relation between R, X and Y. (2 marks)

 13. State Kirchhoff's rules for eletrical networks. (2 marks)

 14. Show that Lenz's law is in accordance with the law of conservation of energy. (2 marks)

 15. Draw a labelled diagram of Hertz's experiment for producing electromagnetic waves. (2 marks)

 16. Give two differences between fringes formed in single slit diffraction and Young's double slit experiment. (2 marks)

 17. Light of wavelength 600nm is incident on an aperture of size 2mm. Calculate the distance up to which the ray of light can travel such that its spread is less than the size of the aperture. (2 marks)

 18. Explain the principle used in Bunsen's grease photometer to compare the illuminating powers of two light sources. (2 marks)

 19. A ray of light while travelling from a denser to a rarer medium undergoes total internal reflection. Derive the expression for the critical angle in terms of the speed of light in the respective media. (2 marks)

 20. Draw a graph showing the variation of binding energy per nucleon with mass number of different nuclei. Mark the region where the nuclei are most stable. (2 marks)

 26. Explain how a vibration magnetometer can be used to determine the magnetic moment of a bar magnet. (3 marks)

 27. Deduce lens maker's formula for a thin biconvex lens. (3 marks)

 28. Explain the origin of spectral lines of hydrogen using Bohr's theory. (3 marks)

 29. A beam of electrons passes undeflected through mutually perpendicular electric and magnetic fields E and B respectively. If the electric field is cut-off ,the electron beam moves in a circular path of radius 'r'.Derive the expression for e/m of electrons in terms of r,E and B. (3 marks)

 30. Draw a labelled diagram of Van de Graff generator.Give its principle and explain its working. (5 marks)

 31. Prove that the power dissipated in an ideal resistor connected to an a.c. source is V2eff/R.Acapacitor,a resistor and a 40 mH inductor are connected in series to an a.c. source of frequency 60 Hz.Calculate the capacitance of the capacitor,if the current is in phase with the voltage. (2+3 marks)

 32. Explain with the help of a circuit diagram the working principle of a transistor as an amplifier in the common emmitter configuration .Derive the expression for the voltage gain of the amplifier.(5 marks)