Question

a monochromaticlight source of power 5mw emits 8×10th the power 15 photons per second. the light ejects photoelectron from a metal surface . the stopping potential for the set up is 2v. calculate the work function of the metal​

Answer 1

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