Practice portal › Dual Nature of Matter and Radiation › Stopping Potential and Threshold Frequency
Asked in NEET Re-exam 2026 · What the stopping potential depends on
Emission needs the incident wavelength to be shorter than the cell's threshold wavelength, λ<λ₀.
Cell 1 has λ₁<λ, so the light is longer than its threshold and no electrons leave. Hence V₁=0.
Cells 2 and 3 have λ₂>λ and λ₃λ, so both of them emit.
For a cell that emits, eV₀=(hc)/λ-(hc)/(λ₀).
The incident term (hc)/λ is the same for both, so the cell with the larger λ₀ subtracts less and ends with the larger V₀.
Since λ₃λ₂, it follows that V₃>V₂, so V₁=0 and V₂<V₃.
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