# Homework Help: Kinetic energy of the photoelectrons

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1. Apr 6, 2016

### manaXmizery

1. The problem statement, all variables and given/known data
A beam of ultraviolet light with wavelength of 200 nm is incident on a metal whose work function is 3.0 eV. Note that this metal is applied with +1.0 V with respect to the ground. Determine the largest kinetic energy of the photoelectrons generated in this process.

2. Relevant equations
Kmax = hf - phi

Kmax = q*|V|

3. The attempt at a solution

I am not entirely sure what the statement about the +1.0 V implies and hence I simply used the formula
Kmax = hf - phi . Substituting the appropriate values gives Kmax = 5.139*10^-19 J . Am I on the correct path ?

2. Apr 6, 2016

### Staff: Mentor

You got the result in the absence of the applied potential. You must now modify the kinetic energy to take into account the potential.

3. Apr 7, 2016

### whatphysics

how do you take into account the potential?

4. Apr 7, 2016

### Staff: Mentor

By calculating its effect on the released photoelectron.