When a monochromatic electromagnetic wave enters a transparent dielectric from vacuum:
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Question

When a monochromatic electromagnetic wave enters a transparent dielectric from vacuum:

G1 Physics · Accepted Answer

The frequency is fixed by the source and does not change at the boundary. Inside a dielectric, v = c/n. Using v = fλ, with unchanged f, λₘ = λ₀/n, where λ₀ is the vacuum wavelength and λₘ is the wavelength in the medium. Therefore frequency remains unchanged while wavelength decreases. Correct option: C.