physics ncert solutions class 11th Physics Class 11th Oscillations

14.1 Which of the following examples represent periodic motion?

(a) A swimmer completing one (return) trip from one bank of a river to the other and back

(b) A freely suspended bar magnet displaced from its N-S direction and released

(c) A hydrogen molecule rotating about its centre of mass

(d) An arrow released from a bow

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1 Answer

Answered by

Vishal Baghel | Contributor-Level 10

5 months ago

(a) The swimmer's motion is not periodic. The motion of the swimmer between the banks of a river is back and forth. However, it does not have a definite period. This is because the time taken by the swimmer during his back and forth journey may not be the same.

(b) The motion of a freely-suspended magnet, if displaced from its N-S direction and released, is periodic. This is because the magnet oscillates about its position with a definite period of time.

(c) When a hydrogen molecule rotates about its centre of mass, it comes to the same position again and again, after an equal interval of time. Such motion is periodic.

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