It takes 254 kJ/mol to eject electrons from a certain metal surface. What is the longest wavelength of light (nm) that can be used to eject electrons from the surface of this metal via the photoelectric effect _ _ ?
A) 233
B) 472
C) 165
D) 552
E) 725

Question

Quizplus · Accepted Answer

The energy required to eject electrons is given by E = hc/λ, where h is Planck's constant and c is the speed of light. Solving for λ gives λ = hc/E. Substituting the given energy (254 kJ/mol) and converting it to J/photon, we find the longest wavelength is approximately 472 nm.

It Takes 254 KJ/mol to Eject Electrons from a Certain