CBSE Class 12 Physics Sample Paper 2014 Set A

1. Draw the equipotential surfaces for two point charges each of magnitude q > 0 placed at some finite distance? 

2. A bar magnet of dipole moment M is cut into two equal parts along its axis. What is the new pole strength of each part. 

3. A rod of length L, along East-West direction is dropped from a height H. if B be the magnetic field due to earth at that place and angle of dip is, then what is the magnitude of induced emf across two ends of the rod when the rod reaches the earth? 

4. Which characteristic of the following electromagnetic waves (i) increases (ii) remains same as we move along -radiation, ultraviolet rays, microwaves and radio waves? 

5. Two polaroids are placed with their optic axis perpendicular to each other. One of them is rotated through 45° what is the intensity of light emerging from the second polaroid if I0 is the intensity of unpolarised light? 

6. Sketch the graph showing the variation of applied voltage and photo electric current for (i) same frequency and two different intensities, and (ii) same intensity and two different frequencies. 

7. What happens to the width of depletion layer of a p-n junction diode when it is (i) forward biased (ii) reverse biased. 

8. Four equal charges +q, –q and +q are placed at the vertices P, Q and R of an equilateral triangle of side ‘a’. What is the electric potential at the centre of the triangle? How will your answer change if position of charges at P and Q are interchanged? 

9. What are ohmic and non-ohmic conductors? Give one example of each. Why can one not measure the resistance of a p-n junction is measured by using a voltmeter? 

10. A charged particle enters a magnetic field perpendicular to it. The particle follows a zigzag path and comes out of it. What happens to its velocity and kinetic energy of the particle? Justify your answer. 

11. Two solenoids each of length L are wound over each other. A₁ and A₂ are the areas of the outer and inner solenoids and N₁ and N₂ are the no. of turns per unit length of the two solenoids. Write the expressions for the self inductances of the two solenoids and their mutual inductance. Hence show that square of the mutual inductance of the two solenoids is less than the product of the self inductances of the two solenoids. 

12. Why two equipotential surfaces do not intersect each other? A charge q₀  is placed at the centre of a conducting sphere of radius R, what is thework done in moving a charge q from one point to other diametrically opposite along the surface of the sphere? 

Please refer to attached file for CBSE Class 12 Physics Sample Paper 2014 Set A