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.