A monochromatic light source of power 5mW emits 8X1015 photons per second This light ejects photoelectrons from a metal - Physics - Moving Charges And Magnetism

Question

A monochromatic light source of power 5mW emits 8X1015 photons per
second This light ejects photoelectrons from a metal surface The
stopping potential for this set up is 2V Calculate the work
function of the metal

Bakul Biswas · Accepted Answer

Dear Student,
Work function is given as
W=E-eV=Pn-eV
Given:
P=5×10-3 WNo
 of electrons, n=8×1015V=2 Ve=1
6×10-19 C

The work function can be calculated as
W=5×10-38×1015-(1 6×10-19×2)=(6 25-3
2)×10-19⇒W=3 05×10-19 J⇒W=3
05×10-191 6×10-19=1 91×10-19 eV

Regards

A monochromatic light source of power 5mW emits 8X1015 photons per second. This light ejects photoelectrons from a metal surface. The stopping potential for this set up is 2V. Calculate the work function of the metal.