Question

In a single slit diffraction experiment, a slit of width is illuminated by the Red light of wavelength $650nm$ . For what value of $a$ will the first maximum fall at an angle of diffraction of ${30}^o$ ?

Answer 1

The position of maximum is given as,

$\left(2n+1\right)\frac{\lambda }{2}=a\sin \theta$

$3\times 650=2a\sin {30}^{\circ }$

$a=1950nm$

$a=1.95\mu m$

Thus, for first maximum fall the value of $a$ is $1.95\mu m$.