When a photon enters glass from air, which one of the following quantity does not change? (a) Velocity (b) Wavelength (c) Momentum (d) Energy

Answer: (d). Frequency depends only on the source, so it does not change on entering glass. Photon energy E = hν depends only on frequency, so E stays the same. Speed, wavelength and momentum p = h/λ all change. So the answer is (d) energy.

When a photon enters glass from air, which one of the following… | MHT CET 2020 (16 Oct, Shift 1)

Q19MHT CET 2020 · 16 OCT · SHIFT 1Easy

Wave Theory, Wavefronts & Doppler Effect

When a photon enters glass from air, which one of the following quantity does not change?

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Answer: (d)

Frequency depends only on the source, so it does not change on entering glass.
Photon energy $E = h\nu$ depends only on frequency, so $E$ stays the same.
Speed, wavelength and momentum $p = h/\lambda$ all change.
So the answer is (d) energy.

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