How Is Kinetic Energy Calculated in the Photoelectric Effect?

[whoopie88]

Homework Statement

A photon with an energy of 15.2 eV enters a hydrogen atom in the ground state and ionizes it. With what kinetic energy will the electron be ejected from the atom?

Homework Equations

Photoelectric Effect equations.

The Attempt at a Solution

E=W+KE

I don't understand how to find the Kinetic Energy with the information I'm given. I need to understand this by tomorrow, so can someone please explain it to me and walk me through the problem ASAP?

Thank you in advance.

 

[ideasrule]

Conservation of energy is all you need. At the beginning, you have a 15.2 eV photon and a second electron in the ground state (what's its energy?). At the end, the photon has been absorbed and all you have is one free electron.

 

[eczeno]

yes, the electron is bound to the proton with a certain energy. you must supply this much to break it free, any extra goes to KE of the electron.