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The work function φ₀ of a metal is best defined as
A{'text': 'The kinetic energy of the fastest photoelectron', 'label': 'A'}
B{'text': 'The frequency of incident light', 'label': 'B'}
C{'text': 'The minimum energy needed to escape from the metal surface', 'label': 'C'}
D{'text': 'The stopping potential at a specific frequency', 'label': 'D'}
Answer & Solution
Correct answer: C. {'text': 'The minimum energy needed to escape from the metal surface', 'label': 'C'}
1. Free electrons in a metal are held by attractive electrostatic forces near the surface.
2. To escape, they must gain a certain minimum energy.
3. That minimum energy is the work function, φ₀, measured typically in eV.
4. It depends on the metal and the state of its surface.
_Source: NCERT Class 12 Physics, Ch 11 "Dual Nature of Radiation and Matter", §11.2_
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