You are Here: Home >< Physics

# Work Function and Threshold Frequency watch

1. Hi,

I've been revising Particle Physics and I'm struggling to understand the relationship between Work Function (WF) and Threshold Frequency (TF).

If I understand correctly, WF is the minimum energy to remove an electron from a metal, whereas the TF is the frequency of the light needed to do so.

How are these related? If I change one what happens to the other? It probably sounds really simple but it's giving me a headache trying to understand it so I was wondering if anyone could put it simply?

Also the equation WF = H x F isn't given in the formula booklet - are we expected to remember this? Where does it come from?

Sorry for all the questions but I really need to get this sorted! Thank you.
2. You need to realise that the energy of an incident photon = hf.

TF is the minimum frequency of the incident photon in order for photoelectric emission to take place, and you can only find this frequency if you knew the metals work function. Since the energy is transferred from the photon to the electron, the electron will need energy that is equal to the work function (or more) to escape from the surface. Therefore, the energy required per photon for photoelectric emission (WF)= H x (minimum frequency of incident photon).

The formula you have typed in is basically E=hf. Only that in this case E is the WF and F is the TF.

Hope that helped.
Hi,

I've been revising Particle Physics and I'm struggling to understand the relationship between Work Function (WF) and Threshold Frequency (TF).

If I understand correctly, WF is the minimum energy to remove an electron from a metal, whereas the TF is the frequency of the light needed to do so.

How are these related? If I change one what happens to the other? It probably sounds really simple but it's giving me a headache trying to understand it so I was wondering if anyone could put it simply?

Also the equation WF = H x F isn't given in the formula booklet - are we expected to remember this? Where does it come from?

Sorry for all the questions but I really need to get this sorted! Thank you.
is the fundamental formula..

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: March 5, 2016
Today on TSR

### University open days

• Sheffield Hallam University
Wed, 17 Oct '18
• Northumbria University
Wed, 17 Oct '18
• Staffordshire University