Q. 53

# The ejection of the photoelectron from the silver metal in the photoelectric effect experiment can be stopped by applying the voltage of 0.35 V when the radiation 256.7 nm is used. Calculate the work function for silver metal.

Answer :

Given:

Work Function of metal, W = 037eV

Wavelength, λ = 256.7 nm

From the Law of conservation of energy, the energy of an incident photon [E] is equal to the sum of the work function [W] of radiation and its kinetic energy [K.E] i.e.,

Energy of incident radiation [E] = hc/λ = [6.626× 10^{-34}] [3× 10^{8}] [256.7× 10^{-9}]

= 7.74× 10^{-19} J

Since the potential applied gives the kinetic energy to the radiation, therefore K.E of the electron = 0.35Ev

Therefore, work function = 4.83 – 0.35

= 4.48 eV

Therefore, the work function of metal is 4.48 eV

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