Question

A test charge ${{q}_{0}}$ is placed in the electric field of a source charge Q. The test charge will not follow path of the electric field line if

Answer 1

Hint : To answer this question we must know what is electric field and what is direction of an electric field. Thus we can define the electric field as the force exerted per unit charge. The electric field will have the direction of force applied on the unit positive charge. For a unit positive charge the field is radially outward and for a negative charge the field is radially inward.

Complete step-by-step solution:
We can define a test charge as a massive particle. Thus the path followed by the test charge is different from that followed by the electric field. This is because of the phenomenon called inertia.
Suppose that the electric field deviates or curves from a space. At this time the test charge continues to move to infinitesimal distance due to inertia in the direction of the electric field. But the test charge changes its direction in the next infinitesimal period.
But as the second infinitesimal path arises the initial velocity points in one direction whereas the acceleration points in a direction such that it is slightly different from the direction of initial velocity.

Note: Remember that when a test charge is moving relative to the source charge, it will experience a fraction of force as the magnetic force. This is given the Lorentz force law. We can also calculate the electric field of a point charge by Coulomb's law.