JEE Main · 2024 · 01 Feb 2024 · Shift 1 · Wave Optics

A monochromatic light of wavelength

6000 \overset{˚}{A}

is incident on the single slit of width 0.01 mm . If the diffraction pattern is formed at the focus of the convex lens of focal length 20 cm , the linear width of the central maximum is :

(A)60 mm
(B)24 mm✓ Correct
(C)120 mm
(D)12 mm

Answer: (B)

Solution

Linear width of the central maximum in single-slit diffraction at the focal plane of a lens of focal length

f

w = \frac{2 f λ}{a} = \frac{2 \times 0.20 \times 6000 \times 1 0 ^{- 10}}{0.01 \times 1 0 ^{- 3}} = \frac{2.4 \times 1 0 ^{- 7}}{1 0 ^{- 5}} = 2.4 \times 1 0^{- 2} m = 24 mm

JEE Main · 2024 · 01 Feb 2024 · Shift 1 · Single correct option

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