Question

A large sphere of charge +Q is fixed in position. A smaller sphere of charge +q is placed near the larger sphere and released from rest then choose the correct option, smaller sphere will move with:

• A. decreasing velocity and decreasing acceleration
• B. decreasing velocity and increasing acceleration
• C. decreasing velocity and constant acceleration
• D. increasing velocity and decreasing acceleration
• E. increasing velocity and increasing acceleration

Answer 1

The correct option is D increasing velocity and decreasing acceleration

Force between charges at distance $r=\frac{kQq}{r^2}$. This force is repulsive in nature. Thus the spheres tend to move away. Since the force remains positive for all values of $r$, the velocity is always increasing.

However the magnitude of force decreases with increasing distance between charges $r$. Thus the acceleration keeps on decreasing.