The momentum of a system is conserved

What is the minimum energy that must be given to a H atom in ground state so that it can emit an H gamma line in Balmer series. If the angular momentum of the system is conserved, what would be the angular momentum of such H gamma photon ?

What is the minimum energy that must be given to a H atom is ground state so that it can emit an H gamma line in Balmer series. If the angular momentum of the system is conserved, what would be the angular momentum of such H gamma photon ?

What is the minimum energy that must be given to a H-atom in ground state so that it can emit an H_gamma line in Balmer series. If the angular momentum of the system is conserved, what would be the angular momentum of such H_gamma photon?

What is the minimum energy that must be given to a H atom in ground state so that it can emit an H_lambda line in Balmer series?If the angular momentum of the system is conserved, what would be the angular momentum of such H_lambda photon?

Statement-1 : Total linear momentum of system in centre of mass frame is zero only when there is no net external force. Statement-2 : Total linear momentum of system is conserved in absence of net external force.

Assertion: A boy is rotating in a rotating chair with some angular speed. Initially arma of the boy are stretched out. When boy folds his hands then angular speed increases Reason: Angular momentum of the system is conserved in absence of external torque.