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### Threshold Energy Definition

Posted: **Sun Apr 15, 2018 3:41 pm**

by **Natalie Noble 1G**

What is the formal definition of threshold energy/work function? I know how to use it in equations but I just would like to know the formal definition. I get it's something relating photons and electrons.

### Re: Threshold Energy Definition

Posted: **Sun Apr 15, 2018 3:41 pm**

by **Fiona Grant 1I**

Threshold energy is the amount of energy per photon that is required to eject electrons from a metal surface.

This is the same thing as the work function, and is represented by the symbol Φ.

### Re: Threshold Energy Definition

Posted: **Sun Apr 15, 2018 3:50 pm**

by **Adrienne B 1J**

The threshold energy is the amount of energy required to move an electron from a certain metal. It is the "phi" symbol in the equation we use for determining the kinetic energy of an electron from last class.

### Re: Threshold Energy Definition

Posted: **Sun Apr 15, 2018 9:54 pm**

by **Chem_Mod**

Threshold energy is the amount of energy per photon that is required to eject electrons from a metal surface.

This is the same thing as the work function, and is represented by the symbol Φ.

Yes, the above is correct. You may have also heard of it as the "work function" of a metal.