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MHT CET 2026 (18 Apr, Shift 1) · Diffraction at a Single Slit

Diffraction at a Single Slit question from MHT CET 2026 (18 Apr, Shift 1)

Q7MHT CET 2026 · 18 APR · SHIFT 1Medium

Diffraction at a Single Slit

In a Fraunhofer diffraction of a single slit, when a slit is illuminated by a light of wavelength $6480$ Å, angular width of central maximum is measured. When the slit is illuminated by light of another wavelength ' $\lambda$ ' the angular width decreases by $25\%$ . The value of $\lambda$ in Å units is

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Answer: (c)

Angular width of central maximum $= \dfrac{2\lambda}{a}$ , so it is $\propto \lambda$ .
Width decreases by $25\%$ : $\lambda = 0.75 \times 6480$ Å
So the answer is (c) $4860$ Å.

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