A source is placed 50 cm from a photocell, and stopping potential is V₀. If the source is moved to 25 cm from the cell, the new stopping potential is:
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Question

A source is placed 50 cm from a photocell, and stopping potential is V₀. If the source is moved to 25 cm from the cell, the new stopping potential is:

G1 Physics · Accepted Answer

Moving the source closer increases the incident intensity, but not its frequency. Einstein’s equation eV₀ = hν − W shows that V₀ depends on frequency and work function, not intensity. Thus stopping potential is unchanged. Answer: B.