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The variation of stopping potential V₀ with frequency u of the incident radiation for a given photosensitive material is a straight line (for u greater than the threshold frequency u₀). The slope of this line is ______.

Asked in GSEB Board March 2023 · Stopping potential and kinetic energy graphs

• (1) h/e
• (2) e/h
• (3) h
• (4) (h u₀)/e

Step-by-step solution

Why the other options are wrong

• (2) e/h is the slope with the axes swapped, that is, of u plotted against V₀.
• (3) h is the slope of Kₘₐₓ (in joules) against u. The stopping potential is (Kₘₐₓ)/e, so its slope carries the extra factor 1/e.
• (4) (h u₀)/e is the size of the intercept on the V₀ axis (the line crosses it at -(h u₀)/e), not the slope.

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