BITSAT2018PhysicsDual Nature of MatterActual
The frequency and the intensity of incident beam of light falling on the surface of a photoelectric material is increased by a factor of two. This will
Options
- Aincrease the maximum kinetic energy of the ejected photoelectrons by a factor of more than two and would incre
- Bincrease the maximum kinetic energy of the photo electron and would increase the photoelectric current both by
- Cincrease the maximum kinetic energy of the photoelectron by a factor of two and will have no effect on the mag
- Dnot produce any effect on the kinetic energy of the emitted photoelectrons but will increase the photoelectric
Correct answer
A. increase the maximum kinetic energy of the ejected photoelectrons by a factor of more than two and would incre
Step-by-step solution
Using Einstein's photoelectric equations, h v = ϕ + e V s e V s = h v - ϕ . . . . ( i ) Thus, when the frequency of incident light radiation (photons) v increases to 2 v , the stopping potential V s changes to V s e V s ' = h ( 2 v ) - ϕ . . . . ii On dividing Eq. (ii) by Eq. (ii), we get V s ' V s = 2 h v - ϕ h v - ϕ = 2 h v - 2 ϕ + ϕ h v - ϕ = 2 ( h v - ϕ ) + ϕ h v - ϕ = 2 + ϕ h v - ϕ ∴   V ' s V s > 2 ⇒ V s ' >