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In the photoelectric effect, the graph of stopping potential (V₀) versus frequency (u) is a straight line. What will be the slope of this straight line?

Asked in GUJCET 2021 · Stopping potential and kinetic energy graphs

• (1) e/h
• (2) (V₀)/h
• (3) h/e
• (4) u/h

Step-by-step solution

Why the other options are wrong

• (1) e/h is upside down -- it would be the slope if frequency were plotted against stopping potential.
• (2) A straight line has the same slope everywhere, so its slope cannot contain the variable V₀. The unit is wrong too: (V₀)/h is in C⁻¹ s⁻¹, while volts per hertz is V s.
• (4) The slope cannot contain the variable u, which changes along the line. Its unit, J⁻¹ s⁻², is not the V s of volts per hertz either.

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