Question Error Report

Thank you for reporting, we will resolve it shortly

Back to Question

Q. In double slit experiment, the wavelength $\lambda$ of the light source $400\, nm$, the slit separation $d$ is $20\, \mu m$ and the individual slit width' $a$ is $4\, \mu m$. Consider the interference of the light from the two slits and also the diffraction of light through each slit. Find number bright interference fringes are within the central peak of diffraction envelope.

Wave Optics

Solution:

We know that
$d \sin \theta=n \lambda$ for interference
and $a \sin \theta=\lambda$ for diffraction
$\therefore \frac{d}{a}=n=\frac{20}{4}=5$.
So interference maxima's is $9$