Question

Monochromatic light of wavelength 650 nm falls normally on a slit of width 1 : 3 × 10^-4 cm and the resulting Fraunhofer diffraction is obtained on a screen. Find the angular width of the central maxima.

Answer 1

λ = 650 × 10^-9 m

Width of slit = `1.3 xx 10^(-4)cm => 1.3 xx 10^(-6)m`

The angular width of central maxima = 2θ → ?

`sintheta = d/d => (650xx10^-9)/(1.3xx10^-6) = 0.5`

θ = 30

2θ → 60° → Angular width of maxima