An electron of mass m and charge q is accelerated from rest in a uniform electric field of strength E. The velocity acquired by it as it travels a distance l is

Options

A. `[(2Eql)/(ql)]^(1/2)`
B. `[(2Eq)/(ml)]^(1/2)`
C. `[(2Em)/(ql)]^(1/2`
D. `[(Eq)/(ml)]^(1/2)`

Answer

A

Explanation

When the electron is accleerated in a uniform electric field, Force/Mass=qE/m and since it starts from rest, and moves in a straight line, we use `v^(2)=u^(2)+2as or v^(2)=0+2 xx (qE)/m xx l therefore v=sqrt(2qEl)/m`.