Question

In experimental set up of Michelson interferometer movable mirror is displaced through $60\mu m$ in distance which causes 300 fringes to cross the field. The wavelength of light must be used to full fill above condition (in nm) is

• A. 600
• B. 400
• C. 200
• D. 100

Answer 1

The correct option is B 400

$n\lambda =2\Delta x$

Given data:

n = 300

$\Delta x=60\mu m$

$\lambda =\frac{2\Delta x}{n}=\frac{2\times 60\times {10}^{-6}}{300}=400nm$