Question

A pendulum makes 135 oscillations in a duration of 15 seconds. What is the time period of the pendulum?

• A. $11.0\text{ms}$
• B. $0.111\text{s}$
• C. $111.0\text{ms}$
• D. $0.111\text{s}$

Answer 1

Answer: (B), (C)

The correct options are
B $0.111\text{s}$
C $111.0\text{ms}$

Given: The pendulum makes 135 oscillations for 15 seconds.
$⟹$ No. of oscillations per second, $n=\frac{135}{15}=9{\text{s}}^{-1}\text{or}9\text{Hz}$

$\therefore$ Frequency, $n=9\text{Hz}$
Time period, $\text{T}=\frac{1}{n}=\frac{1}{9}=0.1111\text{s}=111.11\text{ms}$