Question

In Young's double slit experiment, the slits are separated by $0.56$ mm and the screen is placed $2.8$ cm away. The distance between the central bright fringe and the fifth bright fringe is $1.5$cm. Find the wavelength of light used.

Answer 1

$Y=\frac{n\lambda D}{d}$

here $Y$ is the distance between the fringes=$1.5cm$

$d=0.56mm=0.056cm$ $n=5$

$D=2.8cm$

using the above formula

$1.5=\frac{5\lambda \times 2.8}{0.056}$

$\lambda =0.006cm$