## Velocity of Ejected electron

Alexia Joseph 2B
Posts: 56
Joined: Thu Jul 27, 2017 3:01 am

### Velocity of Ejected electron

Hi I had a question about the work function, specifically from #7 part b on the second quiz that we took. I know we were supposed to use the formula Ek=1/2*m*v^2, but were we supposed to use the work function at all during this part? What exactly is the work function other than being the threshold energy necessary for the energy of the photon to surpass to eject an electron?

lauren chung 2f
Posts: 50
Joined: Fri Sep 29, 2017 7:03 am

### Re: Velocity of Ejected electron

No we were not required to use the work function for #7b

Kimberly Santander3L
Posts: 16
Joined: Fri Sep 25, 2015 3:00 am
Been upvoted: 1 time

### Re: Velocity of Ejected electron

Work function is the energy needed to release an electron from a metal surface.

Sophie 1I
Posts: 51
Joined: Fri Sep 29, 2017 7:04 am

### Re: Velocity of Ejected electron

To find the velocity of the ejected electron you use the kineticE=(1/2)mv^2 equation. You then plug in energy of the ejected electron given to you in part a and set it equal to 1/2 times the mass of an electron times v^2. You do not need to use the work function.

Sophie 1I
Posts: 51
Joined: Fri Sep 29, 2017 7:04 am

### Re: Velocity of Ejected electron

Work functions are used when you are trying to find the kinetic energy of an ejected electron in which case you would take the energy supplied by the photon minus the work function.