Question

A wave produces 40 crests and 40 troughs in 0.2 seconds. Calculate the frequency of the wave.

• A. $200Hz$
  
• B. $300Hz$
  
• C. $400Hz$
  
• D. $500Hz$
  

Answer 1

The correct option is A $200Hz$


We know that one crest and one trough makes one oscillation. Therefore, 40 crests and 40 troughs make 40 oscillations.

The time taken for 40 oscillations = 0.2 s.
Frequency = $\frac{Numberofoscillations}{Timetaken}$ = $\frac{40}{0.2}$ $=200Hz$.