Let neutron be a point mass and hydrogen atom a solid sphere. A neutron makes a head on collision with a hydrogen atom in ground state kept at rest. The coefficient of restitution for collision is e = 1/2 Find the minimum kinetic energy of colliding neutron (in eV) so that hydrogen atom is excited to higher energy level such that magnitude of electrostatic potential energy in the excited state is one-eighth of K.E. of electron in ground state (mass of neutron mass of hydrogen). How many types of power can be defined in an AC circuit?