Question

The surface of a metal is illuminated with the light of 400 nm wavelength. The kinetic

energy of the ejected photoelectron is found to be 1.69 eV. The work function of

the metal is​

Answer 1

Answer:

1.41 eV

Explanation:

Wavelength of the light = 400nm (Given)

Kinetic  energy of the ejected photoelectron = 1.69 eV  (Given)

Conservation of energy = hv = Ф+1/2mv²max or

hc/λ = Ф + (K.E.)max  ( Also known as the Einstein's equation)

where, h is the plank's constant, c is the frequency Ф is the work function

= 1240/400 = Ф + 1.68

= 3.1-1.68

= 1.41ev

Ф = 1.41 eV

Thus, the work function of the metal is 1.41 eV