Question

In a double slit interference experiment, the separation between the slits is $1.0mm$, the wavelength of light used is $5.0\times {10}^{-7}m$ and the distance of the screen from the slits is $1.0m$.
(a) Find the distance of the centre of the first minimum from the centre of the central maximum.

Answer 1

Given that, $d=1mm={10}^{-3}m,D=1m$.
So, fringe with $=\frac{D\lambda }{d}=0.5mm$.
a) So, distance of centre of first minimum from centre of central maximum $=0.5/2mm=0.25mm$