Question

A boat at anchor is rocked by a wave whose crests are $100m$ apart and whose velocity is $25m{s}^{-1}$.how often does the crest reach the boat?

• A. $2500s$
• B. $1500s$
• C. $4.0s$
• D. $0.25s$

Answer 1

The correct option is C $4.0s$

Distance between consecutive crests is the wavelength of the wave.

Here given is $\lambda =100m$

$v=\lambda \nu$

$⟹\nu =\frac{v}{\lambda }$

$⟹\nu =\frac{100m}{25m/s}=4s$