A monochromatic light source of intensity 5 mW emits 8 × 1015 photons per second. This light ejects photoelectrons from a metal surface. The stopping potential for this setup is 2.0 V. Calculate the work function of the metal.

Given, intensity I =5mW,

No. of photons emitted per second n=


Stopping potential V =2V


From Einstein’s photoelectric equation,


work function



=


=




Work function Ф =1.906eV


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