Question

A charged particle of charge $q=1\mu C$ and mass m $=$ 1g is released from rest in a uniform electric field E $=$ 100 volt/m. Neglecting the effect of gravity, the kinetic energy of the charged particle after 2 seconds is :

• A. $20J$
• B. $20\mu J$
• C. $1\mu J$
• D. $1mJ$

Answer 1

Answer: (B)

$20\mu J$

Electric field is uniform
$a=\frac{qE}{m}=0.1m/se{c}^2$
$v=0+\left(0.1\right)\times 2=0.2m/sec$
$KE=\frac{1}{2}m{v}^2=20\mu J$