Photoelectric Effect

[dcm18]

I was wondering if anyone could help me with this question....

 

What is the maximum number of electrons that can be emitted if a potassium surface of work function 2.40 eV absorbs 3.25 x 10^-19 J of radiation at a wavelength of 300 nm? What is the kinetic energy and velocity of the electrons emitted?

 

I really have no idea so any help would be much appreciated.

 

Thanks

[timo]

1) What's the energy for one photon of wavelength 300 nm ?

2) Assuming it's enough to free an electron, what will the resultant energy of the electron be?

3) What's the velocity of an electron with that energy?

4) How many photons of wavelength 300 mn are in 3.25x10^-19 J ?

5) (not part of the question): Ask yourself why that's the/an upper limit and not the actual number.

6) If you did my numbers step by step without really knowing what's going on, get off your computer and try to understand why I have chosen this order of steps.

[dcm18]

Thank you that was very helpful