Question

The phase difference between the two light waves reaching at a point $P$ is $100\pi$. Their path difference is equal to

• A. $10\lambda$
• B. $25\lambda$
• C. $50\lambda$
• D. $100\lambda$

Answer 1

Answer: (C)

Given, $\Delta \varphi =100\pi$
We know, change in phase difference,
i.e., $\Delta \varphi =\frac{2\pi }{\lambda }\times \Delta x$
where, $\Delta x=$ path difference
$\Rightarrow \Delta x=\Delta \varphi \times \frac{\lambda }{2\pi }$
$=100\pi \times \frac{\lambda }{2\pi }=50\lambda$