Chapter-1|Electric Charges and Fields | NCERT 12th Physics:
The electric field due to a charge q at a point in space may be defined as the force that a unit positive charge would experience if place at that point.
Electric Field Intensity:
The electric field intensity at any point due to source charge is defined as the force experienced per unit positive test charge placed at that point without disturbing the source charge.
Note:- (l) Electric field due to positive charge (+q) is directed radially outward i.e away from positive charge.
(ll) Electric field due to negative charge (-q) is directed radially inward i.e. toward negative charge.