How Much Energy Does an Electron Retain from Blue-Green Light?

[Marcus James]

Homework Statement

If an electron in metallic cesium absorbs a photon of red light (6.6x10^-7) m in vacuum), all the energy is used up in escaping from the attractive forces in the metal. Suppose light with 5x10^-7 is used, what percentage of the photon's energy does the electron retain after it has escaped from the metal? What color light is this?

Homework Equations

The Attempt at a Solution

I believe the light color would be that of Blue-Green.[/B]

 

[phinds]

And why do you think that? Do you have any math to support it?

 

[Marcus James]

Because Blue-Green is the medium between Blue (4.5-5)x10^-7 and Green (5.0-5.7)x10^-7, as the light in this example is 5x10^-7, so it falls between the two. Have you any though on the first question?

 

[Doc Al]

Have you any though on the first question?

How do the energies of the two photons compare?