Question

What is the phase difference between two successive crests in the wave?

• A. $\pi$
• B. $\frac{\pi }{2}$
• C. $2\pi$
• D. $4\pi$

Answer 1

The correct option is C $2\pi$

Phase difference between any two particles in a wave determines lack of harmony in the vibrating state of two particles, ie, how far one particle leads the other or lags behind the other.
Relation of path difference and phase difference is given by
$\Delta \varphi =\frac{2\pi }{\lambda }\times \Delta x$
where $\Delta x$ is path difference.
But path difference between two crests
$\Delta x=\lambda$
Hence, $\Delta \varphi =\frac{2\pi }{\lambda }\times \lambda =2\pi$