Question

(a) What is meant by the 'time-period' of a vibrating object? State its unit.

(b) Define 'frequency' of a vibrating object. Name the unit in which frequency is measured.

(c) A pendulum oscillates 40 times in 4 seconds. Calculate its (i) time-period. and (ii) frequency. Can we hear the sound produced by the oscillations of this pendulum? Give reason for your answer.

Answer 1

(a) The time taken to complete one oscillation is called as time period. The unit is seconds.

(b) A vibrating object whose number of oscillations per second is known as its frequency. The unit of frequency of vibration or oscillation of a vibrating object is hertz. When an object makes one vibration per second its frequency is said to be 1 hertz. If an object makes 10 vibrations per second , then its frequency will be 10 hertz.

(c) Time period $=\frac{Totaltime}{Noofvibrations}=\frac{4}{40}=0.1s$

frequency = $\frac{1}{T}=\frac{1}{0.1}=10Hz$