When light passes from air into another medium, its speed changes. Which property of light stays unchanged during this transition?
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e. Frequency.
When light passes from air into another medium (like water or glass), its speed and wavelength change due to the medium’s refractive index. However, the frequency of light remains constant, as it is determined by the source and does not depend on the medium.
Why others are incorrect:
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A. Wavelength: Changes because speed changes (v=fλv = f \lambdav=fλ).
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C. Speed: Changes according to the medium (v=c/nv = c/nv=c/n).
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D. Amplitude: Can change depending on absorption or reflection, so it is not guaranteed to stay the same.