Question

In Young's double-slit experiment, ligth of wavelength $5000\mathring{A}$ is used. The thire bright band on the screen is formed at a distance of $1cm$ from the central bright band.if the screen is at a distance of $1.5m$ from the centre of the two narrow slits, calculate the separation between the slits.

Answer 1

$\begin{array}{c}\lambda =5000A^{\circ }\\ n=3\\ D=1.5m\\ wkt,\\ \beta =\frac{n\lambda D}{d}\\ d=\frac{n\lambda D}{\beta }=\frac{3\times 5000\times {10}^{-10}\times 1.5}{{10}^{-2}}=225\times {10}^{-6}m\\ d=0.0225cm\end{array}$