Question

In double-slit experiment using light of wavelength 600 nm, the angular width of a fringe formed on a distant screen is ${0.1}^{\circ }$. What is the spacing between the two slits?

Answer 1

Wavelength of light used, $\lambda =600\times {10}^{-9}m$

Angular width of fringe, $\theta ={0.1}^o=0.1\pi /180$

Angular width of a fringe is related to slit spacing as $d=\lambda /\theta =3.44\times {10}^{-4}m$

So, the spacing between the slits is $3.44\times {10}^{-4}m$