Question

What will be the angular separation of the first order fringe from the central maximum, when a light of wavelength 500 nm is diffracted at a slit of width 0.5 mm?

(a) 2.1 minute

(b) 3.4 minute

(c) 4.8 minute

(d) 5.6 minute

I have been asked this question by my college director while I was bunking the class.

My question is based upon Diffraction of Light topic in division Diffraction of Engineering Physics II

Answer 1

The correct option is (b) 3.4 minute

To elaborate: a = 0.5 mm = 0.5 X 10^-3m, λ = 5000 Å = 5 X 10^-7 m.

Angular separation between the central maximum and the first order minimum is given by:

sin θ = \(\frac{\lambda}{a}\) = 0.001

sin θ ≈ θ

θ = 0.001 radian

θ = 3.4 minute.