Question 10

MODEL QUESTION PAPER –SERIES TEST III

MAXIMUM TIME: 1 HOUR MAXIMUM MARKS: 25

Answer any 5 questions choosing atleast 2 questions from each part
PART A

1. Explain phase velocity, group velocity and particle velocity and write down the relation between them.
2. Show that electrons cannot exist in the nucleus of an atom.
3. State Mathiessien’s rule and give an account of the nature of total resistivity both at high and low temperatures.
4. What is the polarization produced in sodium chloride by an electric field of 600 Volts/mm if it has a dielectric constant of 6?

PART B

5. Describe with energy band diagram the construction and working of semiconductor diode laser.
6. The attenuation of an optical fibre is -3.6 dB/km. What is the fraction of light that remains 1) after 1 km 2) after 3km?
7. Explain with neat sketch the diamond crystal.
8. Describe a method of measuring the velocity of ultrasonic waves in solids.