JEE Main202331 Jan 2023Morning ShiftPhysicsNuclear PhysicsActual
A free neutron decays into a proton but a free proton does not decay into neutron. This is because
Options
- Aneutron is an uncharged particle
- Bproton is a charged particle
- Cneutron is a composite particle made of a proton and an electron
- Dneutron has larger rest mass than proton
Correct answer
D. neutron has larger rest mass than proton
Step-by-step solution
Mass of the neutron is m n = 1 . 67493 × 10 - 27   kg , mass of the proton is m p = 1 . 67262 × 10 - 27   kg . Proton's rest mass is less than that of a neutron's rest mass. As particle can not decay to a state of greater mass, hence the proton does not decay to neutron outside nucleus whereas the neutron can decay into a proton though β -decay.