JEE Main202228 Jul 2022Evening ShiftPhysicsDual Nature of MatterActual
Two streams of photons, possessing energies to five and ten times the work function of metal are incident on the metal surface successively. The ratio of the maximum velocities of the photoelectron emitted, in the two cases respectively, will be
Options
- A1 : 2
- B1 : 3
- C2 : 3
- D3 : 2
Correct answer
C. 2 : 3
Step-by-step solution
Using Einstein's photoelectric equation, Maximum kinetic energy, K E m a x = E - ϕ , where, E is energy of photon and ϕ is work function. For two cases, 1 2 m v 1 2 = 5 ϕ - ϕ = 4 ϕ and 1 2 m v 2 2 = 10 ϕ - ϕ = 9 ϕ Thus, the ratio v 1 v 2 = 4 9 = 2 3 = 2 : 3