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What would be the intercept on the Y-axis of the graph of stopping potential (V₀) → frequency (f)? [f > f₀]

Asked in GSEB Board March 2020 (old course) · Work function from a graph

• (1) e/h
• (2) -e/(hf₀)
• (3) h/e
• (4) -(hf₀)/e

Step-by-step solution

Why the other options are wrong

• (1) e/h is the reciprocal of the slope and is not even a voltage (its unit is V⁻¹ s⁻¹). A line that rises from f₀ must cut the Y-axis below the origin, so the intercept is negative.
• (2) The sign is right but the fraction is upside down: putting f = 0 in V₀ = h/e(f - f₀) gives -(hf₀)/e. The unit of e/(hf₀) is V⁻¹, so it cannot be a potential.
• (3) h/e is the slope of the line, not the point where it cuts the Y-axis.

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