Relating Work Function and Wavelength

[ri0t]

Homework Statement

Barium has a work function of 2.48 eV. What is the longest wavelength of light that will cause electrons to be emitted from barium?

Homework Equations

W = hf○
hf = W + Ek
E = hf = hc/λ

The Attempt at a Solution

1 eV/1.6e-19 C = 2.48/X
X = 3.97e-19

W=hf○
3.97e-19/6.63e-34f
f=5.99e14 Hz

Now I'm lost...Anybody care to help? :)

 

[hage567]

So what's the relationship between frequency and wavelength? You've already used it (look at equation 3).

 

[ri0t]

So what's the relationship between frequency and wavelength? You've already used it (look at equation 3).

I think I've figured out the problem using v=fλ, 3.0e8 = 5.98e14λ, λ=5.02e-7m.

Also the answer to your question is that as frequency increases, wavelength decreases.

Would be awesome if you could tell me I'm on the right track, and of course if I'm not, as well.

 

[hage567]

Yes, you are right.

 

[ri0t]

Thanks much.