x Turn on thread page Beta
 You are Here: Home >< Physics

# photoelectric effect (need help) watch

1. so i need help with this question and im too frustrated to think straight, i think i have some answers but there probably wrong. So here it is

The stopping potential when a frequency of 1.61*10^15 Hz is shone on a metal is 3V

a) what is energy transferred by each photon ?
b)calculate the work function of the metal
c)What is the maximum speed of the ejected electrons
2. (Original post by nebbercracker)
so i need help with this question and im too frustrated to think straight, i think i have some answers but there probably wrong. So here it is

The stopping potential when a frequency of 1.61*10^15 Hz is shone on a metal is 3V

a) what is energy transferred by each photon ?
b)calculate the work function of the metal
c)What is the maximum speed of the ejected electrons
Right down the answers you have got, and I'll see if they match with mine. Also did you use the correct equations? And if you did, what equations did you use?
3. (Original post by Reety)
Right down the answers you have got, and I'll see if they match with mine. Also did you use the correct equations? And if you did, what equations did you use?
well for part a i did E=hv so energy = planks * velocity which for a photon is the speed of light

6.63*10^-34 x 300,000,000 m/s = 1.989*10^-25

then for part b i used the equation work function = hf-E so planks * frequency - energy

6.63*10^-34 x 1.61*10^15 - 1.989*10^-25 = 1.0674*10^-18

for part c I didn't know what equation to use and it was pretty late at night when i attempted all this so i gave up.
So do these two answers seem right ?
4. (Original post by nebbercracker)
so i need help with this question and im too frustrated to think straight, i think i have some answers but there probably wrong. So here it is

The stopping potential when a frequency of 1.61*10^15 Hz is shone on a metal is 3V

a) what is energy transferred by each photon ?
b)calculate the work function of the metal
c)What is the maximum speed of the ejected electrons
a) E = hf
b) E_kmax = hf - (phi)
c) E)kmax = hf - (phi) where E_kmax = 1/2 m v^2
5. (Original post by nebbercracker)
so i need help with this question and im too frustrated to think straight, i think i have some answers but there probably wrong. So here it is

The stopping potential when a frequency of 1.61*10^15 Hz is shone on a metal is 3V

a) what is energy transferred by each photon ?
b)calculate the work function of the metal
c)What is the maximum speed of the ejected electrons
a) E = hf

b) hf = work function - KE (max) ==> KE (max) = work function - hf

However, the KE (max) of the electron = eV, where V is the stopping potential.

Therefore, KE max = 1.6 x 10^(-19) x 3

c) KE max = 0.5 x m x v^2, and just rearrange to find v.

TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Updated: February 4, 2016
Today on TSR

### Loughborough better than Cambridge

Loughborough at number one

### Can I date a girl with no boobs?

Poll

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE