Question

In a field, the force experienced by a charge depends upon its velocity and becomes zero, when it is at rest. What is the nature of the field?

Answer 1

Force experienced by charge in a magnetic field is given by

$\overrightarrow{F}=q(\overrightarrow{\vartheta }\ast \overrightarrow{B})$

and in this case when $\vartheta =0$ force becomes zero.

In case of electric field, force is given by $F=qE$ and force will always act as the charge whether it is at rest or motion.