## Example from Class- Photoelectric Effect

chrisavalos-2L
Posts: 63
Joined: Fri Sep 28, 2018 12:18 am

### Example from Class- Photoelectric Effect

If 3.61x10^-19 J is required to remove an electron with the kinetic energy from a metal surface, what would be the longest wavelength light that could do this?

I was wondering how to set up the problem initially, I know the concept of what we are looking for but I'm not sure on the initial set up?

Carine Tamamian 2B
Posts: 61
Joined: Fri Sep 28, 2018 12:23 am

### Re: Example from Class- Photoelectric Effect

What we did in class, we combined the two equations, E=hv and c=λv. Solving for λ would give you λ=c/v, and solving for v in the first equation will give v=E/h.
Substitute the v into the λ equation, which will give λ=hc/E. Once you have this equation, plug in all your given.
λ=(6.626*10^-34 Js)(3.00*10^8 m/s)/(3.6*10^-19 J)=551.*10^-9 m

Andrea Zheng 1H
Posts: 61
Joined: Fri Sep 28, 2018 12:26 am

### Re: Example from Class- Photoelectric Effect

You would use the equations E=h*(freq) and c=(wavelength)*(freq). From these equations, you derive the equation wavelength=(h*c)/(E). Because you are given E, h, and c, you can then solve for wavelength.