NTA Abhyas JEE Main2020PhysicsAtomic PhysicsPractice
An electron of a stationary hydrogen atom (mass = m ) jumps from the fifth energy level to the ground level. As a result, the atom emits a photon and recoils with some velocity. The velocity that the atom acquires as a result of photon emission is [ h = Planck's constant, R = Rydberg's constant]
Options
- A24 hR 25 m
- B25 hR 24 m
- C24 m 25 hR
- D25 m 24 hR
Correct answer
A. 24 hR 25 m
Step-by-step solution
Here, E 5 − E 1 = hc λ − ( Rhc 5 2 − Rhc ) = hc λ (where R = Rydberg's constant, h = Planck's constant and c = speed of light in vacuum) ⇒ 24 25 R = 1 λ But P = h λ ⇒ v = h mλ = 24 Rh 25 m