- #1
fireandwater
- 3
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Hi. I hope someone can help. Here is the problem:
[Pennies are made of zinc coated with copper. Copper has a work function of 4.7eV. The ozone layer blocks nearly all solar radiation with wavelength shorter than 320nm, but a very small amount of 200nm light still manages to reach the Earth's surface. Can direct sunlight produce photoelectrons from a penny?]
I converted the 4.7eV into joules: 4.7eV * 1.602e-19J = 7.529e-19J
I found the minimum kinetic energy needed to for the electrons to escape from the copper:
KE = e * V_o => 1.602e-19 * 7.529e-19 = 1.206e-37J
I'm thinking that I need to use the 200nm to find out whether the kinetic energy I calculated will be produced by the sunlight, but I don't see how to do that.
[Pennies are made of zinc coated with copper. Copper has a work function of 4.7eV. The ozone layer blocks nearly all solar radiation with wavelength shorter than 320nm, but a very small amount of 200nm light still manages to reach the Earth's surface. Can direct sunlight produce photoelectrons from a penny?]
I converted the 4.7eV into joules: 4.7eV * 1.602e-19J = 7.529e-19J
I found the minimum kinetic energy needed to for the electrons to escape from the copper:
KE = e * V_o => 1.602e-19 * 7.529e-19 = 1.206e-37J
I'm thinking that I need to use the 200nm to find out whether the kinetic energy I calculated will be produced by the sunlight, but I don't see how to do that.