Electron,proton, neutron and alpha particle have same momentum which particle has more kinetic energy?

2 Answers
Aug 9, 2018

Smaller the mass of the particle, larger its kinetic energy.

Explanation:

Let M be the constant momentum, then as M=mv, where m is mass and v is velocity, then vprop1/m

and as kinetic energy (KE) is given by 1/2mv^2, we have

KEpropmv^2 or KEprop(mxx1/m^2)

i.e. KEprop1/m

Hence smaller the mass of the particle, larger its kinetic energy

i.e. electron has most kinetic energy.

Aug 9, 2018

Kinetic energy in terms of momentum vecp is given by the expression

KE=|vecp|^2/(2m)
where m is the mass of particle.

It is given that momentum of all four particles Electron, proton, neutron and alpha particle is same. Above expression reduces to

KEprop1/m

Out of given particles, electron has the lowest mass. Therefore, electron has the maximum kinetic energy.