## How to find the longest wavelength?

$c=\lambda v$

Lauren Lewis3L
Posts: 57
Joined: Wed Feb 20, 2019 12:16 am

### How to find the longest wavelength?

To find the longest wavelength in the photoelectric effect is it just taking the energy minus the work function and set it equal to the Kinetic Energy? Wouldn't the Ek be equal to zero for the longest wavelength?

Julie_Reyes1B
Posts: 105
Joined: Sat Jul 20, 2019 12:16 am

### Re: How to find the longest wavelength?

Yes, that is all correct. The photon energy would then equal the work function. You have to convert the work function into the units J/e- and then solve for whatever variable you need.
Last edited by Julie_Reyes1B on Sun Nov 10, 2019 11:04 pm, edited 1 time in total.

jeffreygong1I
Posts: 49
Joined: Thu Jul 11, 2019 12:15 am

### Re: How to find the longest wavelength?

Just find the wavelength of light with energy equal to the work function.

005321227
Posts: 90
Joined: Sat Sep 07, 2019 12:15 am

### Re: How to find the longest wavelength?

find the wavelength of light equal to the work function

CalvinTNguyen2D
Posts: 102
Joined: Thu Jul 25, 2019 12:16 am

### Re: How to find the longest wavelength?

The longest wavelength correlates with the same amount of energy of the work function. Just set Ep and the Work Function equal to one another and solve for the wavelength!

Sydney Pell 2E
Posts: 100
Joined: Wed Sep 11, 2019 12:17 am

### Re: How to find the longest wavelength?

The kintetic energy (Ek) would be equal to zero because if you want to find the longest wavelength of light that is able to eject an electron, that means that there is no energy left over (Ek) because all of it is used to eject the electron (the work function). So, set the energy of the photon (Ep) equal to the work function to solve for the longest wavelength.

Noah Canio 3C
Posts: 55
Joined: Wed Sep 18, 2019 12:20 am

### Re: How to find the longest wavelength?

The longest wavelength, as everyone mentioned, comes from the work function. Using the value of energy from the work function, solve for wavelength using E = h(c)/(wavelength).