The rest mass of a proton is `1.67xx10^(-27)` kg Its total energy when it moves with a speed of `2.1 xx10^(8)` m/s is

Options

A. `2.105xx10^(-10) J`
B. `20.16xx10^(-10) J`
C. `2.105xx10^(-9) J`
D. `20.15xx10^(-9) J`

Answer

A

Explanation

`m=m_(0)/sqrt(1-v^(2)/c^(2))=(1.67xx10^(-27))/sqrt(1-((2.1xx10^(8))/(3xx10^(8)))^(2))`
`m=2.3386xx10^(-27) kg`
`:. E= mc^(2)`
`=2.3386xx10^(-27)xx9xx10^(16)`
`=2.105xx10^(-10) J`