Question

An electron of mass 'm' and charge 'q' is accelerated from rest in the electric field 'E'. The velocity acquired by the electron in travelling a distance 'x' is ______ 

Options

• (Em/qx)^1/2 

• (Eq/mx)^1/2 

• (2Eqx/m)^1/2 

• (2Eq/mx)^1/2 

Answer 1

An electron of mass 'm' and charge 'q' is accelerated from rest in the electric field 'E'. The velocity acquired by the electron in traveling a distance 'x' is (2Eqx/m)^1/2.

Explanation:

The force on electron F = qE

Acceleration a = `F/m = (q"/"m)/m`

v² = 2ax = `2 xx (qE)/m xx x`

∴ v = `sqrt((2Eqx)/m)`