question_answer

As an electron makes a transition from an excited state to the ground state of a hydrogen - like atom / ion:     [JEE MAIN 2015]

A) kinetic energy decrease, potential energy increase but total energy remains same

B) kinetic energy and total energy decrease but potential energy increases

C) its kinetic energy increases but potential energy and total energy decrease

D) kinetic energy, potential energy and total energy decrease

Correct Answer: C

Solution :

[c] Speed of electron in the orbit is given by

An orbit number decreases, velocity of electron increases and results in increase in K.E.

Potential energy is given by P.E. = – 2K.E, so Potential energy decreases

Total energy is given by T.E. = – K.E., so total energy of electron also decreases.