Threshold Freq. and WOrk Function (1 Viewer)

[Validity]

Why do electrons have 0 KE at threshold frequency?

btw im trying to show work function= h x threshold frequency

 

[nightweaver066]

Why do electrons have 0 KE at threshold frequency?

btw im trying to show work function= h x threshold frequency

First lets define a few terms.

The work function is the MINIMUM energy incident required on a metal surface such that an electron is emitted with ZERO kinetic energy.

The threshold frequency is the frequency of light that is able to provide energy exactly equal to the work function (nothing more nothing less).

So therefore at the threshold frequency, electrons will have 0 KE.

So from these definitions, you can gather than the work function = h x threshold frequency by Planck's equation, E = hf.

where Ei is the energy of incident light, phi is the work function and KE is the kinetic energy of the emitted electron.



When f_i is the threshold frequency, KE must equal to 0

 

[Validity]

if it has zero KE at the threshold frequency, then doesn't that mean the the electrodes can't get ejected?

 

[nightweaver066]

if it has zero KE at the threshold frequency, then doesn't that mean the the electrodes can't get ejected?

They're ejected as in they're removed from the electron orbit it was in with the nucleus of a metal atom.

 

[Validity]

oh so it doesn't necessarily have to fly off the metal ?

 

[nightweaver066]

oh so it doesn't necessarily have to fly off the metal ?

Nope, flying off the metal = KE.