10051 2 ॥।॥॥॥ | ॥॥ |

PART-B
Answer any 10 questions. Each question carries 4 marks.

13. Whatare the conditions for oscillations of a harmonic oscillator to be over damped,
critically damped and under damped ? Compare the time — displacement curve
in the three cases. ⋪

14. Apiece of wire 50 cm long is stretched by a load of 2.5 kg and has a mass of 1.44g.
Find the frequency of the second harmonic.

15. Light of wave length 6000 A falls normally on two glass plates enclosing a
wedge shaped film. The plates touch at one end and are separated at 10 cm from

that end by a wire. If the bandwidth of the interference pattern is 0.05 mm, find
the diameter of the wire.

16. Light of wave length 589.3 nm is incident normally on a plane transmission
grating having 6000 lines/cm. Calculate the angle at which the principal maxima
of the first order is formed.

17. How do you distinguish circularly polarized light from un polarized light ?
18. Write any four applications of superconductors.
19. What are the conditions to be satisfied by a wave function ?

20. What is phase space ? With the help of Heisenberg’s Uncertainty relation, show
that the minimum size of the unit cell in quantum statistics is hf, where h is the
Planck's constant and f is the degree of freedom of the system.

21. The dimensions of an auditorium are 60 m x 15 mx 10 m and its interior surfaces
have an average absorption co-efficient of 0.25.Find the reverberation time of
the auditorium.

22. Given that the velocity of ultrasonic waves in sea water is equal to 1440 m/s.
Find the depth of a submerged submarine, if ultrasonic pulses reflected from the
submarine is received 0.33 s after sending ultrasonic waves.

23. With the help of a neat diagram explain how a hologram is recorded.

24. A fibre cable has an acceptance angle of 30° and a core of refractive index 1.4.
Calculate the refractive index of the cladding.