Given below are two statements: Assertion (A): Even for a very high intensity of incident light, if its frequency is below the threshold frequency, no photoelectrons are emitted from a metal surface.

Question

Given below are two statements:

Assertion (A): Even for a very high intensity of incident light, if its frequency is below the threshold frequency, no photoelectrons are emitted from a metal surface.

Reason (R): The photoelectric effect is a quantum phenomenon where a single photon interacts with a single electron, and the energy of a photon depends only on its frequency.

TestHub · Accepted Answer

The photoelectric effect depends on the energy of individual photons ( $h ν$ ) exceeding the work function ( $ϕ$ ). If $h ν < ϕ$ , no electron can be ejected, regardless of the number of photons (intensity).

The reason correctly explains this quantum nature where photon energy is frequency-dependent, thus justifying why intensity alone cannot cause emission below threshold frequency.

Physics - Modern Physics Question with Solution | TestHub

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