The momentum of a photon having energy equal to the rest energy of an electron is

Options

A. zero
B. `2.73 xx 10^(-22)kg ms^(-1)`
C. `1.99 xx 10^(-24)kg ms^(-1)`
D. infinite

Answer

B

Explanation

For photon, `p=(h)/(lambda)=(E)/(c )`
But from questions,
E = rest energy of electron = `m_(0)c^(2)`
`thereforep=(m_(0)c^(2))/(c )=m_(0)c=(9.109xx10^(-31)kg)xx(3xx10^(8)ms^(-1))`
`=2.7327 xx 10^(-22)kgms^(-1)=2.73xx10^(-22)kg m//s`