Answer
The correct answer is:
(d) the photon loses energy so that the scattered photon has a frequency less than $f$
Work Step by Step
In the Compton effect, a photon scatters off a stationary electron. The recoiling electron takes some energy from the photon, so the scattered photon has less than its original energy. A photon with less energy has a longer wavelength and a lower frequency.
The correct answer is:
(d) the photon loses energy so that the scattered photon has a frequency less than $f$
