Question

A hydrogen atom, and a doubly ionised lithium (Li)⁺⁺ atom, are in their first exerted state and the second excited state, respectively. If l_H and l_Li are the respective angular momenta, and K_H , K_Li are the, respective, kinetic energies, of the electron, in the two atoms, we can say that 

Answer 1

Correct option : (3)

Explanation :

For the hydrogen atom n_H = 2 and z_H = 1 

For the doubly ionised lithium atom, we have n_Li = 3; and z_Li = 3 

According to Bohr’s first postulate, the angular momentum of electron, in an orbit, is directly proportional to n; therefore;

The K.E of the electron, is an orbit, equals the |T.E.| and T.E ∝ z²/n²;  therefore