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The volume of a hall is 6000 ന്‌. It has a total absorption of 150m? 58010. If the
hall is filledwith audience who add another 80 m? sabin, find the difference in
reverberation time.
An ultrasonic source of 0.085 MHz sends down a pulse towards the sea water
which returnsafter 0.6 sec. The velocity of sound in water is 1800m/s. Calculate
the depth of the sea and wavelength of pulse.
With the help of a diagram explain how a hologram is recorded?
Give any four advantages of optical fibre over conventional transmission lines?
PART C

Answer any three questions. Each question carries 6 marks
Considering transverse vibrations of a stretched string derive one dimensional
wave equation.
Draw the neat diagram of air wedge experiment.
Derive an expression for the bandwidth of the interference fringes using this
arrangement.
Given two Nicol prisms and a Quarter wave plate. How can we produce and
analyseplane,circularly and elliptically polarized light.
Starting from the time dependent equation, derive Schrodinger’s time
independent wave equation.

PART D

Answer any three questions. Each question carries 6 marks
Define Reverberation and Reverberation time.
What is the significance of Reverberation time? Compare Reverberation and
Echo.
What is inverse piezoelectric effect?
Describe the method of producing ultrasonic waves using this effect.
Draw the energy level diagram and explain the working of He-Ne laser.
What are the important applications of He-Ne Laser?
Define numerical aperture and fibre acceptance angle of an optic fibre.

Derive an expression for numerical aperture (NA) of a step indexfibre.
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