Question

A neutron of kinetic energy K eV collides inelastically with a singly ionized
helium atom at rest in ground state. Neutron moves perpendicularly to its
initial direction of motion after collision and helium atom gets excited to first
state. If a particle moves at 30° to initial direction of motion of neutron, then
value of nearest integer) is

Answer 1

45 is the answer.........