Solving V and eV Questions: Work Function & Threshold Frequency

[dangsy]

Homework Statement

Light of the wavelength Lambda = 5893 Angstrom is incident on a surface. The stopping potential for the emitted electrons is 0.36 volt. Calc the max energy of the photoelectron, the work function and threshold frequency.


my question is about the stopping potential, the problem is given in volts, how do I convert to eV? does "emitted electrons" indicate it as an Electron volt in words, so that the eV would be 0.36?

Thanks!

 

[blochwave]

Well volts and eV are fundamentally different

an eV is energy, you could, for example, express it in joules if you wanted to

a volt is a unit of potential difference

An eV is how much energy an electron would have after being accelerated across one volt of potential difference

 

[dangsy]

If I took the 0.36V and multiplies by e = (1.6E-19) would that give me an eV? I'm also not understanding your explanation very well, is there any other way to put it?

Thanks!

 

[mda]

If I took the 0.36V and multiplies by e = (1.6E-19) would that give me an eV?

Yes, that tells you how many Joules in 0.36eV.

 

[dangsy]

so...just to make sure...

if I'm given volts I can multiply by e (1.6E-19) to get eV?

so 0.36V x 1.6E-19 = 5.76E-20eV?

Thanks!

 

[mda]

No, 0.36eV = 5.76E-20 J

 

[dangsy]

But if the problem gives Volts as in "The stopping potential for the emitted electrons is 0.36 volt"

how do I get eV out of this?

 

[mda]

Then the electron energy associated with this potential is 0.36eV, which as you have shown is 5.76E-20 J. Generally energy = charge * potential.