Question

A progressive wave of frequency $500Hz$ is travelling with a velocity $360m{s}^{-1}$. How far are two points ${60}^{\circ }$ out of phase?

• A. $0.06m$
• B. $0.12m$
• C. $0.18m$
• D. $0.24m$

Answer 1

Answer: (B)

$0.12m$

Frequency $f=500$ Hz.
Wavelength
$\lambda =\frac{v}{f}=360/500m$
Since $\lambda$ corresponds to $2\pi ={360}^o$ phase change, ${60}^o$ phase change =$\frac{360}{500}\times \frac{60}{360}=0.12m$