Question

Please ans this question.....i have uploaded a picture... Please ans fast i have my exam tomorrow

Answer 1

One crest and and one trough constitutes one cycle.

40 crests and 40 troughs involves 40 cycles.

Time taken for one cycle is called time period.

So, Time period = 0.4 s / (40) = 0.01 s

Frequency = 1 / Time period = 1 / (0.01 s) = 100 Hz

PLZ MARK BRAINLIEST! Best of luck for your exam tomorrow!

Answer 2

Since the sound wave produces 20 crests in 0.2 second, the density of the medium at a place becomes maximum 20 times in 0.2 second. The number of times it becomes maximum in 1 second is

\begin{lgathered}\sf \frac{20}{0.2} \\ \\ \sf 10 \times 10 \\ \\ \sf 100\end{lgathered}0.22010×10100 

So, the frequency is 100 times /second or 100 Hz.