Question

The wavelength of incident light is 4000A°. What is the minimum change in the light energy..?​

Answer 1

Explanation:

we know that ,

maximum energy of emitted photons electron KE energy of the incidence radiation - work functions

= 12.37eV

now the Kinetic energy is

KE = 12.37 -2

= 10.37eV

hence the kinetic energy is 10.37eV

Answer 2

4.97 ×-16 J

Explanation:

The kinetic energy of the photons emitted by the metal surface is given by the Einstein's equation of photo electric effect.

KE = Light energy incident - Work function

The work function is a constant for the metal.So the increase in light energy is the energy present in the photons incident.

h = Planck's constant

Light energy= h × frequency

E = h c / lambda

= (6.626 ×10−34 J s × 3×10^8 m/s) / (4000× 10^-10 m) J

= 4.97 ×-16 J