29.2 Exercise 1

A metal exposed to a beam of light with a wavelength equal to or shorter than a specific wavelength emits electrons. What property of light, as described in the quantum explanation of blackbody radiation, accounts for this photoelectric process?

1. The energy of light increases as its speed increases.
2. The energy of light increases as its intensity increases.
3. The energy of light increases as its frequency increases.
4. The energy of light increases as its wavelength increases.