MCAT Physics Question 122: Answer and Explanation

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Question: 122

2. What is the wavelength of a photon that causes an electron to be emitted from a metal with a kinetic energy of 50 J? (Note: The work function of the metal is 16 J, and h = 6.626 × 10^-34 J·s)

A. 1.0 × 10^-34 m
B. 3.0 × 10^-27 m
C. 3.0 × 10^-26 m
D. 1.0 × 10³⁵ m

Correct Answer: B

Explanation:

To determine the wavelength of the light ray, first calculate its frequency from the photoelectric effect equation:

Next, determine the wavelength of the incident ray of light by relating the frequency to the speed of light:

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