Assume an electron in a hydrogen atom undergoes a transition from n = 3 to n = 2 in 10⁻⁸ s . Using the standard relation between torque and angular momentum, the order of magnitude of the torque acting on the electron during this period is

Step-by-step solution

The angular momentum of an electron in the n -th orbit of a hydrogen atom is given by L = nh 2 . The change in angular momentum during the transition from n = 3 to n = 2 is L = L₃ - L₂ = 3h 2 - 2h 2 = h 2 Substituting the value of Planck constant h = 6.63 10⁻³⁴ J s , we get L = 6.63 10⁻³⁴ 2 1.05 10⁻³⁴ J s The average torque acting on the electron is the rate of change of angular momentum: = L t Given the transition time t = 10⁻⁸ s , the torque is = 1.05 10⁻³⁴ 10⁻⁸ = 1.05 10⁻²⁶ N m The order of magnitude of the torq