Monochromatic light shines on a surface that has a work function of 1.80 eV. The maximum kinetic energy of the emitted photoelectrons is 0.620 eV. What is the wavelength of the monochromatic light?
A) 200 nm
B) 290 nm
C) 689 nm
D) 602 nm
E) 512 nm

Question

Quizplus · Accepted Answer

The energy of the incident light is the sum of the work function and the maximum kinetic energy of the photoelectrons: E = 1.80 eV + 0.620 eV = 2.42 eV. Using the relation E = hc/λ, where h is Planck's constant and c is the speed of light, we find λ = hc/E. Converting 2.42 eV to joules and using the known values of h and c, the wavelength λ is approximately 512 nm.

Monochromatic Light Shines on a Surface That Has a Work