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MHT CET 2026 (12 May, Shift 2) · Wave Theory, Wavefronts & Doppler Effect

Wave Theory, Wavefronts & Doppler Effect question from MHT CET 2026 (12 May, Shift 2)

Q3MHT CET 2026 · 12 MAY · SHIFT 2Easy

Wave Theory, Wavefronts & Doppler Effect

A Parallel beam of monochromatic light is incident on a plane reflecting surface. If width of the plane incident and reflected plane wavefront is represented by $AB$ and $CD$ respectively then

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Answer: (c)

On reflection the wave stays in the same medium, so speed is unchanged.
Hence angle of reflection = angle of incidence, $r = i$ .
Widths: $AB = L\cos i$ and $CD = L\cos r$ for the same length $L$ of the surface.
So the answer is (c) $AB = CD$ .

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