# A particle of mass m and charge q is released from rest in a uniform electric field.

Question:

A particle of mass $m$ and charge $q$ is released from rest in a uniform electric field. If there is no other force on the particle, the dependence of its speed $v$ on the distance $x$ travelled by it is correctly given by (graphs are schematic and not drawn to scale)

Correct Option: , 2

Solution:

Using

$v^{2}-u^{2}=2 a S$                       ...(1)

Here, $u=0, s=x$

Also, $F_{\text {electric }}=m a$

Substituting the values in (i) we get

$v^{2}=\frac{2 q E}{m} \cdot x$

$\Rightarrow q E=m a$

$\Rightarrow a=\frac{q E}{m}$