A pendulum swings in backward and forward direction passing through Y, the middle point of the oscillation.
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?

Options

A. T/40
B. T/21
C. T/20
D. T/10

Answer

D

Explanation

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

Here, 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 period = ("Time taken")/("Number of oscillations")= T/(10)`