Exam-style question
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If the work function of a metal is 3.2 eV, what is the minimum energy of a photon required to emit an electron?.
- A.1.6 x 10^-19 J
- B.3.2 x 10^-19 J
- C.4.8 x 10^-19 J
- D.6.4 x 10^-19 J
Model answer
What a good answer should say
- 3.2 x 10^-19 J
Explanation
Why this works
The minimum energy required to emit an electron is equal to the work function. To convert the work function from eV to joules, use the conversion 1 eV = 1.6 x 10^-19 J.
Therefore, 3.2 eV = 3.2 x 1.6 x 10^-19 J = 5.12 x 10^-19 J. The correct answer is 3.2 x 10^-19 J.
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