question_answer

A pendulum swings backwards and forwards passing through Y, middle point of the oscillation.     

The first time the pendulum passes through Y, a  stopwatch is started.

The twenty-first time the pendulum pass through Y, the stopwatch is stopped. The reading is T.

What is the time period of the pendulum?

A) 7740               

B) 7721   

C) 7720           

D) 7710

Correct Answer: D

Solution :

The time taken to complete one oscillation is called the time period of a pendulum.

Here the time period is the time taken to move from Y to B then back to A and then to Y. The reading of stopwatch = T Number of oscillations = 10 \[\therefore \] Time taken \[=\frac{Time\text{ }period}{Number\text{ }of\text{ }oscillations}\] \[=\frac{T}{10}\]