A beam of red light and a beam of violet light each deliver the same power on a surface. For which beam is the number of photons hitting the surface per second the greatest?
A)the red beam
B)the violet beam
C)The number of photons per second is the same for both beams.
D)This cannot be answered without knowing just what the light intensity is.

Question

Quizplus · Accepted Answer

Red light has a longer wavelength and therefore lower energy per photon compared to violet light. To deliver the same power, the red beam must have more photons per second.

A Beam of Red Light and a Beam of Violet