Question

Wavelength of wave is a distance between two particles which are differing in phase by

• A. $\pi$
• B. $2\pi$
• C. $\frac{2\pi }{3}$
• D. $\frac{\pi }{3}$

Answer 1

The correct option is B $2\pi$

At a given time ($t=$ constant) the phase change with position $x$. Phase change at a given time for a distance $\Delta x$ is
$\Delta \varphi =-\frac{2\pi }{\lambda }\times \Delta x$
As, the distance between two crests is $\lambda$
For distance $\lambda$, the phase change is
$\Delta \varphi =\frac{2\pi }{\lambda }\cdot \lambda =2\pi$