31

32

00000PH100121805

after 0.6 s. Calculate the depth of the sea. Velocity of sound in sea water is 1800
m/s.

Give any two applications of ultrasonic waves in medical field.

What are Einstein’s coefficients? Using Einstein’s coefficients show that at
normal conditions rate of spontaneous emission is predominant. What are the
conditions required to increase stimulated emission?

What are fibre optic sensors? Explain the working of intensity modulated

sensor.

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