Q.

In single slit diffraction pattern, the wavelength of light used is 628 nm and slit width is 0.2 mm, the angular width of central maximum is α×10-2 degrees. The value of α is ______.                [2026]


Ans.

(36)

Wavelength (λ)=628 nm=628×10-9 m

Slit width a=0.2 mm=2×10-4 m

For Single Slit diffraction,

Angular width of central maxima θ=2λa

θ=2λa=2×628×10-92×10-4=6.28×10-3 radian

in degree =180π≃57.3°

θ=6.28×10-3×57.3≃0.36°

θ=36×10-2 degree

θ=6.28×10-3×57.3≃0.36°

⇒θ=36