What is the work function of the metal?

[xlzhsteven]

Light of 300 nm wavelength strikes a metal plate, and photoelectrons are produced moving as fast of 0.002c. What is the work function of the metal?

 

[hage567]

What have you tried so far? Please show what work you've done. We don't give out solutions here.

 

[xlzhsteven]

I don't know what equations to use. Do I have to use the moving speed to find the energy, but I don't know how to use that 300nm since it's not the cutoff wavelength.

 

[borgwal]

The electrons have an "excess" energy: so the work function should equal the difference between the photon energy and the excess energy.

 

[xlzhsteven]

Should I use 0.5mv^2=hc/wavelength-work function, then what should I use for the mass in 0.5mv^2, the mass of an electron?

 

[hage567]

Yes, you use the mass of an electron.

 

[xlzhsteven]

So I have 3.108 for the answer of the work function

 

[xlzhsteven]

is that right?

 

[hage567]

Seems reasonable to me.

 

[borgwal]

Your answer should contain the correct unit, though!

 

[xlzhsteven]

3.108eV

 

[borgwal]

okay, that sounds like the right order of magnitude.