NCERT Physics Class 11 Exemplar Ch 14 Oscillations Part 3

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19. Displacement versus time curve for a particle executing S.H.M. is shown in Fig. 7. Identify the points marked at which (i) velocity of the oscillator is zero, (ii) speed of the oscillator is maximum.

Displacement versus time

Displacement Versus Time

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Ans: (i) (A), (C), (E), (G)

(ii) (B), (D), (F), (H)

20. Two identical springs of spring constant K are attached to a block of mass m and to fixed supports as shown in Fig. When the mass is displaced from equilibrium position by a distance x towards right, find the restoring force

Two spring of spring constant

Two Spring of Spring Constant

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Ans: towards left.

21. What are the two basic characteristics of a simple harmonic motion?

Ans: (a) Acceleration is directly proportional to displacement.

(b) Acceleration is directed opposite to displacement.

22. When will the motion of a simple pendulum be simple harmonic?

Ans: When the bob of the pendulum is displaced from the mean position so that

23. What is the ratio of maximum acceleration to the maximum velocity of a simple harmonic oscillator?


24. What is the ratio between the distance travelled by the oscillator in one time period and amplitude?

Ans: Four

25. In Fig, what will be the sign of the velocity of the point P′, which is the projection of the velocity of the reference particle P. P is moving in a circle of radius R in anticlockwise direction?

Velocity of point P

Velocity of Point P

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Ans: -ve

26. Show that for a particle executing S.H.M, velocity and displacement have a phase difference of.

27. Draw a graph to show the variation of P.E., K.E. and total energy of a simple harmonic oscillator with displacement.


Draw a graph variation total energy

Draw a Graph Variation Total Energy

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28. The length of a second’s pendulum on the surface of Earth is 1m. What will be the length of a second’s pendulum on the moon?