A parallel beam of monochromatic light of wavelength 460 nm passes through a long slit of width 0.1 mm. What is the angular divergence in which most of the light is diffracted?

$9.2 × 10^{-3} rad$

The correct answer is Option (3) → $9.2 × 10^{-3} rad$

To find the angular divergence in most of light is diffracted, we use the formula for single slit is -

$\sin θ=\frac{mλ}{α}$

for first diffraction (m = 1), the angle $θ$ corresponds for the divergence.

$\sin θ=\frac{λ}{α}=\frac{460×10^{-9}}{0.1×10^{-3}}=4.6×10^{-3}$ radians