Question

The time period of a simple pendulum depends on:
(a). Mass of pendulum bob
(b). Length of pendulum
(c). The combined mass of bob and thread
(d). None of the above

Answer 1

- Hint: Use the mathematical expression of a time period of a simple pendulum. Then observe the mathematical formulae to find the quantities on which the time period depends.

Complete step-by-step solution -

A simple pendulum consists of a string of length l, whose one end is attached to a fixed point and another end is attached to a freely moving bob of mass m. We can observe a to and fro motion in a simple pendulum. This to and fro motion depicts simple harmonic motion or S.H.M.
The time taken by the pendulum to complete one oscillation is known as the time period of the pendulum. In mathematical terms, we can write it as:
$ T= 2 \pi \times \sqrt{ \dfrac{L}{g} }$
Thus, the time period depends on:
Length of the pendulum
Acceleration due to gravity

Hence, option (b) is correct.

Additional Information:
Pendulums are basically categorized as 4 types:
Simple pendulum
Compound pendulum
Conical pendulum
Torsional pendulum

Pendulums can be used for the following purposes:
To keep time
To keep the beat.
In a seismometer
For religious practices
In coupled pendulums

Note: You can perform experiments to find the time period of a pendulum using different length and mass. This will help in a better understanding of the concept. The time period of the bob is independent of the mass of the bob or that of the thread. Thus, both options A and C are incorrect.