The relationship between the time period (T) of a wave and its frequency (f) is given by the following formula:
f = 1 / T
Where:
f = frequency (measured in Hertz, Hz)
T = time period (measured in seconds, s)
In this case, the time period (T) is given as 0.02 s.
Let's calculate the frequency:
f = 1 / 0.02 s
f = 50 Hz
Therefore, the frequency of the sound wave is 50 Hz.