SECTION - A
Note: a) Answer all questions.
b) Every question carries 2 marks.
c) All are very short answer type questions. 10 x 2 = 20
1. If slits in Young's double slit experiment are illuminated with
white light which coloured fringe will be closer to the central
2. Light is reflected from a lead glass plate with index of refraction
1.96. At what angle of incidence must light strike the plate so that the reflected ray is completely plane polarized?
3. What do you mean by Curie temperature?
4. Write Gauss's law in electrostatics.
5. State Faraday's and Lenz's laws in Electro magnetics.
6. A transformer converts 100 V ac into 1000V a.c and has 10 turns in its primary. What is the number of turnings in secondary.
7. State Moseley's law and its importance.
8. How does the width of the depletion layer change in a p-n junction diode i) When it is forward-biased ii) and when reverse biased?
9. Write the truth table for NAND gate. How does it differ from AND gate?
10. What do you mean by modulation?
SECTION - B
Note: a) Answer any Six questions.
b) Every question carries 4 marks.
c) All are short answer type questions. 6 x 4 = 24
11. Explain the working of simple microscope and derive an expression for its magnifying power.
12. Derive an expression for magnetic induction at a point on the
equatorial line of a bar magnet.
13. Two positive charges q1 = 4x10-6 C and q2 = 9x10-6 C are placed at 10 cm apart mutually, in air. Find the position of a third charge placed between them such that resultant force is zero on it.
14. A battery of emf 6 V and internal resistance 1Ω gives potential
difference of 5.8 V when connected to an external resistance. Find the external resistance.
15. Explain the principle of Potentio meter.
16. Using a graph explain how thermo emf changes with temperature hence state neutral and inverse temperatures.
17. What do you mean by photo electric effect? Explain it using
18. What is a Zener diode? How it is possible to use it as a Voltage regulator.
SECTION - C
Note: a) Answer any two questions.
b) Each question carries 8 marks.
c) All are long answer type questions. 2 x 8 = 16
19. What is Doppler effect? Find an expression for the apparent frequency heard when the source is in motion and the listner
is at rest. What is the limitation of Doppler effect?
A train is travelling at 120 Kmph and blows a whistle of frequency
1000 Hz. What is the apparent frequency as heard by the stationary observer if the train approaching him?
20. Obtain an expression for torque on a current carrying loop placed in a uniform magnetic field. Describe the construction and working of moving coil galvanometer.
21. Define mass defect and binding energy of a nucleus. Draw the model graph showing relation between average binding energy and mass number and explain its characteristics.
SECTION - A