What is the physical meaning of the 'Work Function' of a metal in the context of the photoelectric effect? MCQ with Answer and Explanation

What is the physical meaning of the 'Work Function' of a metal in the context of the photoelectric effect?
A. The minimum energy required to eject an electron from the metal surface.
B. The electrical resistance of the metal when light shines on it.
C. The maximum kinetic energy of an emitted electron.
D. The total energy of an incident photon.
Answer: Option A
Solution (By JKExamLibrary)
In Einstein's photoelectric theory, electrons are bound to the metal lattice. The 'work function' (often denoted by Phi or W) is defined strictly as the absolute minimum thermodynamic work (energy) needed to overcome these binding forces and remove an electron from the surface into a vacuum. If incident photon energy (hf) is less than the work function, absolutely no emission occurs.

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This question belongs to: Science Physics