Propagation of Sound Waves — Question 5

Given,

One crest and one trough make one wave, hence there are 40 waves.

time (t) = 0.4 s

frequency f = ?

Frequency is the number of waves per second,

$\text f = \dfrac{40}{0.4} \\[0.5em] \Rightarrow \text f = 100 \text { Hz}$

Hence,

Frequency of the wave = 100 Hz