Chapter 27, Problem 9Q

To determine

If light of the same intensity but of wavelength 400 nm strikes the surface, are more electrons emitted? Does the energy of the emitted electrons change?

Answer to Problem 9Q

Solution:

The number of electrons emitted does not depend on the frequency of the light. The energy of the emitted electrons changes.

Explanation of Solution

The emission of electrons or other free carriers when light shines on a material. The number of electrons emitted does not depend on the frequency of the light, but on the intensity of the light. Therefore, the 400nm waves cause the same amount of electrons to be emitted. However, because the frequency of the 400nm light is greater, the maximum kinetic energy of the ejected electrons is higher.