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If the photoelectric effect is not seen with ultraviolet radiation for a given metal, photoelectrons may be emitted with ______.

Asked in GSEB Board July 2015 · Threshold frequency

Answer: (3) X-rays

Step-by-step solution

Given: ultraviolet light does not eject electrons from this metal.

Idea: an electron is emitted only if one photon's energy h u is at least the work function φ₀, that is, only if u ≥ u₀.

So the threshold frequency u₀ of this metal lies above the ultraviolet frequencies used.

Of the options, only X-rays have a higher frequency than ultraviolet; infrared, radio waves and visible light are all lower.

So photoelectrons may be emitted with X-rays.

Why the other options are wrong

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