An electron is accelerated through a potential difference of `200` volts. If `e//m` for the electron be `1.6 xx 10^(11)` coulomb/kg, the velocity acquired by the electron will be

Options

A. `8xx10^(6)ms^(-1)`
B. `8xx10^(5)ms^(-1)`
C. `5.9xx10^(6) ms^(-1)`
D. `5.9xx10^(5) ms^(-1)`

Answer

A

Explanation

`(1)/(2)mv^(2)=eV`
or `v+sqrt((2eV)/(m))=sqrt(2xx1.6xx10^(11)xx200)ms^(-1)=8xx10^(6)ms^(-1)`