As a distant star moves away from Earth, the light given off by the star has a measurably lower frequency. What happens to the wavelength and energy of the photons of light when the frequency becomes lower?
a. The wavelength becomes longer, and the energy decreases.
b. The wavelength becomes shorter, and the energy decreases.
c. The wavelength becomes longer, and the energy increases.
d. The wavelength becomes shorter, and the energy increases.