Ans. In order to find the value of electric intensity at a point in the field, of charge +q, we place a test charge q0 at that point (Fig. 13.7). If F is the force acting on the test charge q0, the electric field intensity would be given by
q° Thus, electric field intensity at any point is defined as:
The force acting on a unit positive charge placed at that point is known as electric field intensity.
Unit: The SI unit of electric intensity is newton per coulomb (NC~r).
If the electric field due to a given charge is known at some point, the force on any particle with charge q placed at that point can be calculated by using the formula: .
F = qE