JEE Main · 2024 · 27 Jan 2024 · Shift 2 · Wave Optics

A parallel beam of monochromatic light of wavelength

5000 \overset{˚}{A}

is incident normally on a single narrow slit of width 0.001 mm. The light is focused by convex lens on screen, placed on its focal plane. The first minima will be formed for the angle of diffraction of ____ (degree).

Answer: 30

Solution

For a single slit of width

a

, the first diffraction minimum occurs at

a sin θ = λ

. With

λ = 5000 \overset{˚}{A} = 5 \times 1 0^{- 7} m

and

a = 0.001 mm = 1 0^{- 6} m

sin θ = \frac{λ}{a} = \frac{5 \times 1 0 ^{- 7}}{1 0 ^{- 6}} = \frac{1}{2} ⟹ θ = 3 0^{\circ} .

JEE Main · 2024 · 27 Jan 2024 · Shift 2 · Integer answer

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