29.

30.

31,

32.

33.

34,

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D 43195

A body having a mass of 4 g. execute The force acting on the body, when

8 simple harmonic motion,
displacement is 8 em.

, 15 24 gm. wt. Find the Period.

A particle of mass 10 g. lies in a potential field V = 2
oscillation. P eld 50 x* + 100 ergs/gm. Deduce the frequency of

The frequency of the fourth harmonic in a stretched string of len
the velocity of the wave in the string ?

If the intensity of sound wave is increased by a factor of 20

i » by how many decibels is the sound
level increased.

(4 x 4 = 16 marks)
Section E

Answer any two questions.
Each question carries 10 marks.

Obtain an expression for couple per unit twist of a wire. Explain how the rigidity modulus of a
wire can be determined using a torsion pendulum.

Deduce the equation for the simple harmonic motion of a particle. Show that the resultant of two
simple harmonic motions having the same period but different phase and amplitude are acting in
the same direction on a particle is simple harmonic. What are the uses of Lissajous figures ?

Derive an expression for a plane progressive harmonic wave. Derive the expression for energy
density and energy current for such a wave.

What are ultrasonic waves ? Explain the production of ultrasonic wave by piezoelectric crystal
method. What are the applications of ultrasonic waves ?

(2 x 10 = 20 marks)