Question

An observer on the sea shore observes $54$ waves reaching the coast per minute. If the wavelength is $10m$, the velocity is

• A. $9m{s}^{-1}$
• B. $54m{s}^{-1}$
• C. $18m{s}^{-1}$
• D. $36m{s}^{-1}$

Answer 1

The correct option is A $9m{s}^{-1}$

Frequency ($f$) is given as :

Number of waves traveling per unit second.

According to the question frequency (f) of the sea wave will be given as :

$f=\frac{54}{60}=\frac{9}{10}Hz$

We know that velocity of the wave is given as :

$v=\lambda \times f$

Substituting the value of $\lambda$ and $f$

$v=\frac{9}{10}\times 10v=9m/s$