A parallel beam of light of wave length 500 nm in incident normally on a single slit of width $10^{-6}m$. The light is focused by a convex lens on a screen placed in focal plane. What is the angle of diffraction for the first minimum formed?
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → 30°
The condition for minima,
[m = order of minimum] $a\sin θ=mλ$
[a = width of the slit]
[θ = Angle of diffraction]
$⇒10^{-6}\sin θ=1×500×10^{-9}$
$⇒\sin θ=0.5$
$⇒θ=\sin^{-1}\left(\frac{1}{2}\right)=30°$