Question

The path difference between two monochromatic light waves of wavelength $4000\mathring{A}$ is $2\times {10}^{-7}m$. The phase difference between them is

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

Answer 1

The correct option is A $\pi$

Path difference, $\Delta x=2\times {10}^{-7}m$

Wavelength of light used, $\lambda =4000A^o=4\times {10}^{-7}m$

Phase difference, $\varphi =\frac{2\pi }{\lambda }\times \Delta x$

$\therefore$ $\varphi =\frac{2\pi }{4\times {10}^{-7}}\times 2\times {10}^{-7}=\pi$