Question

a) If the work function for a certain metal is 1.8 eV, What is the stopping potential for electrons ejected from the metal when light of wavelength 400 nm shines on the metal?
b) What is the maximum speed of the ejected electrons?

Answer 1

The energy of the photoemission electrons is

E = [ h*c/(wavelength)] - 1.8 V* e

(a) Divide that by electron charge (e) for the stopping potential.

(b) Use E = (1/2)m V^2 to solve for V