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The maximum kinetic energy KEₘₐₓ of an electron is given as 10 eV, and the work function ϕ is 2.75 eV. Calculate the total incident energy E.

1. E = KEₘₐₓ + ϕ
2. E = KEₘₐₓ − ϕ
3. E = ϕ − KEₘₐₓ
4. E = KEₘₐₓ × ϕ

Correct answer: E = KEₘₐₓ + ϕ

Solution

The total incident energy E is the sum of the maximum kinetic energy KEₘₐₓ of the electron and the work function ϕ, as per the photoelectric equation: E = KEₘₐₓ + ϕ.

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