A parallel beam of monochromatic light of wavelength 450 nm passes through a long slit of width 0.2 mm. What is angular divergence in which most of the light is diffracted?

Question

A parallel beam of monochromatic light of wavelength 450 nm passes through a long slit of width 0.2 mm. What is angular divergence in which most of the light is diffracted? (A) 4.5 × 10-3 rad (B) 2 × 10-4 rad (C) 4 × 10-3 rad (D) 4.5 × 10-4 rad

Tardigrade Admin · Accepted Answer

Most of light is diffracted between two first order minima a sin θ=λ sin 0=0=(450 × 10-9/0.2 × 10-3) =± 2.25 × 10-3 Angular divergence =2 θ=2 × 2.25 × 10-3 =4.5 × 10-3 rad

Q. A parallel beam of monochromatic light of wavelength $450 nm$ passes through a long slit of width $0.2 mm$ . What is angular divergence in which most of the light is diffracted?

$4.5 \times 1 0^{- 3} r a d$

$2 \times 1 0^{- 4} r a d$

$4 \times 1 0^{- 3} r a d$

$4.5 \times 1 0^{- 4} r a d$

Most of light is diffracted between two first order minima
a $sin θ = λ$
$sin 0 = 0 = \frac{450 \times 1 0 ^{- 9}}{0.2 \times 1 0 ^{- 3}}$
$= \pm 2.25 \times 1 0^{- 3}$
Angular divergence $= 2 θ = 2 \times 2.25 \times 1 0^{- 3}$
$= 4.5 \times 1 0^{- 3} r a d$

Q. A parallel beam of monochromatic light of wavelength 450nm passes through a long slit of width 0.2mm. What is angular divergence in which most of the light is diffracted?

4.5×10−3rad

2×10−4rad

4×10−3rad

4.5×10−4rad