Question

Light of wavelength 2500Å falls on a metal surface of work function 3.5V. What is the kinetic energy (in eV) of (i) the fastest and (ii) the slowest electronic emitted from the surface? If the same light falls on another surface of work function 5.5eV, what will be the energy of emitted electrons?

Answer 1

Wavelength of incident radiation (λ) = 2500Å

Work function (W₀) =3.5eV

(i) KE of fastest electron =1.47eV
(ii) KE of slowest electron = 0eV
If the same light (having energy 4. 97eV) falls on the surface (of work function 5.5eV), then no photoelectrons will emit.