JEE Main 2019 Physics question

PhysicsSystems of Particles and Rotational MotionJEE Main 2019

An alpha-particle of mass m suffers 1-dimensional elastic collision with a nucleus at rest of unknown mass. It is scattered directly backwards losing 64% of its initial kinetic energy. The mass of the nucleus is:

Answer: (B)

Solution

⇒ M = 4m.

Question ID VK-010214