Question

What is meant by diffraction? Light of wavelength $5000\stackrel{o}{A}$ is falling normally on a slit of width $2\times {10}^{-5}$m. Find the angular width of the central maxima in the diffraction pattern.

Answer 1

Diffraction of light is the phenomenon of bending of light ray at the sharp edge of the obstacle placed in its path.
Given : $\lambda =5000A^o=5\times {10}^{-7}m$
Slit width $d=2\times {10}^{-5}m$
Angular width of central maxima $\theta =\frac{2\lambda }{d}$
$⟹\theta =\frac{2\times 5\times {10}^{-7}}{2\times {10}^{-5}}=0.05$ radian