Question

The separation betweenthe consecutive darki fringes in a young's double slit experiment is 1.0 mm. The screen is placed at a distance of 2.5 m from the slits an the separation between the slits is 1.0 mm. Calculate the wavelength of light used for the experiment.

Answer 1

Given that, $b=1mm={10}^{-3}m,D=2.5mandd=1mm={10}^{-3}mSo,{10}^{-3}m=\frac{2.5\times \lambda }{{10}^{-3}}\Rightarrow \lambda =\frac{1}{2.5}{10}^{-6}m=4\times {10}^{-7}m=400nm$