Target Exam

CUET

Subject

Physics

Chapter

Wave Optics

Question:

First diffraction minima due to a single slit of width $1.0 × 10^{–5} cm$ is at 30°. Then wavelength of light used is

Options:

400 Å

500 Å

600 Å

700 Å

Correct Answer:

500 Å

Explanation:

As $a\, \sin θ = nλ$ or $λ=\frac{a\, \sin θ}{n}$

or $λ=1.0×10^{-5}×\sin 30°=1.0×10^{-5}×\frac{1}{2}$

$= 0.5 × 10^{–5} = 5 × 10^{–6} cm$

$=500 Å$