Question

How is fringe width of an interference pattern in Young's double slit experiment affected if the two slits are brought closer to each other?

Answer 1

fringe width of interference pattern in Young's slit experiment is given by $\beta =\frac{\lambda D}{d}$

where, $d$ is the distance between the two slits, $D$ is the distance between the slit and the screen and $\lambda$ is the wavelength of light used.

$⟹$ $\beta \propto \frac{1}{d}$

Thus fringe width of the interference pattern increases as we decrease the distance between the two slits.