Electric Field - Practice Questions & MCQ

Electric field and electric lines of force:

The space around a charge in which another charged particle experiences a force is said to have an electric field in it. 

Electric Field Intensity: 

The electric field intensity at any point is defined as the force experienced by a unit positive charge placed at that point.

Electric field intensity,

where F is the force experienced by q0. The SI unit of E is,

The dimensional formula is  

The electric field is a vector quantity and due to positive charge is away from the charge and for the negative charge, it is towards the charge.

Electric field due to a point charge: 

Consider a point charge placed at the origin O. Let a test charge q0 is placed at P which is at a distance r from O. Force F on test charge q0 is

The electric field at point P due to q is

(As q_o tends to zero the electric field produced by q is not affected by q_o.)

The magnitude of the electric field 

Electric field due to a system of charge:

Electric field obeys the superposition principle. That is the electric field due to a system of charge at a point is equal to the vector sum of all the electric fields.