Kinetic energy of ejected Electrons

[Natalie Swerdlow 3K]

If a light shining on a material causes electrons to be ejected with negligible KE, what happens to the quantity of electrons emitted and kinetic energy of the ejected electrons when the intensity of the light is decreased?

The answer is that the quantity of electrons decreases, but the kinetic energy stays the same.

Why does the kinetic energy stay the same in this instance?

[Brian Chau 1D]

It helps to think about this question with photons as packets of energy. If you are decreasing intensity, it's just decreasing the amount of photons interacting with the metal surface but the energy of each photon remains the same. As a result, all that changes is that less photons are ejecting electrons from the surface but each photon is ejecting each electron with the same amount of KE.

[Nika Kononov 3E]

I think the kinetic energy always stays the same because the speed of the light is not changed (it's always 3*10^8m/s). So the electrons are hit with less intensity but at the same speed so their kinetic energy wouldn't change.

[RossLechner3E]

When you say intensity this is referring to the sheer number of photons emitted from the light. Ejecting an electron is a 1:1 photon electron interaction. Assuming wavelength is constant from the change, we know velocity will remain constant because c is the speed for all photons, we are only decreasing the frequency of the interaction, therefore the electrons will still be ejected at the same velocity but simply less of them.