Question

A source of wave produces 20 compressions and 20 rarefactions in 0.2 sec. What is the frequency of the wave?

Answer 1

Firstly, you have to calculate the number of waves in given compression as well as rarefaction. After that, calculate waves produced in 0.2 sec. Then, find the frequency of the resulting wave that is produced in the given second.

Complete step-by-step solution:
Since, 1 complete wave has 1 compression as well as 1 rarefaction.
Which means that 20 compressions and 20 rarefactions are equal to 20 waves.
Therefore, In 0.2 sec number of waves are produced = 20 Waves
Now, In 1 sec number of waves are produced :-
$=\dfrac{20}{0.2}$
$=\dfrac{20\times 10}{2}$
$=100$Waves
Frequency of 1 wave that is produced = 1 Hz
Frequency of 100 wave that are produced = 100 Hz

Additional Information:
Wave is defined as the propagation of disturbances from place to place in a regular and organized way. Most familiar are surface waves that travel on water, but sound and light exhibit wavelike properties. Also, In the simplest waves, the disturbances oscillate periodically with a fixed frequency as well as wavelength. Mechanical waves such as the sound, require a medium through which to travel or pass, while electromagnetic waves do not require a medium and can be propagated through a vacuum. While, Propagation of a wave through a medium depends on the medium's properties.

Note: Always, first calculate the number of the waves. Only after that, find the frequency. This means that you have to always follow the prescribed manner to get an accurate result as well as to get rid of confusion.