1.The electric field lines never intersect. justify?

If two lines cross at a point, then there will be two different electric field vectors at the same point If some charge is placed in the intersection point, then it has to move in two different directions at the same time, which is physically impossible. Hence, electric field lines do not intersect.

2.Define electric flux & Give its unit?

The number of electric field lines crossing a given area kept normal to the electric field lines is called electric flux.

It is usually denoted by the Greek letter ΦE and its unit is Nm² C^–1 

3.Define capacitance. Give its units?

The capacitance C of a capacitor is defined as the ratio of the magnitude of charge on either of the conductor plates to the potential difference existing between them.

The SI unit of capacitance is coulomb per volt or farad (F)

4.What is corona discharge?

The electric field near the edge of conductor is very high and it ionizes the surrounding air. The positive ions are repelled at the sharp edge and negative ions are attracted towards the sharper edge. This reduces the total charge of the conductor near the sharp edge. This is called action of points or corona discharge.

5.Define electric dipole. Give an example?

Two equal and opposite charges separated by a small distance constitute an electric dipole.

p = 2qa

Examples : h₂o,Hcl,co₂

6.State coulomb’s law in electrostatics?

The electrostatic force experienced by the charge q due to q is given by Coulomb’s law.

7.Write short note on electrostatic shielding?

The electric field inside the cavity of a conductor is zero. A sensitive electrical instrument which is to be protected from external electrical disturbance can be kept inside this cavity. This is called electrostatic shielding

8.What is meant by electric field lines?

They form a set of continuous lines which are the visual representation of the electric field in some region of space

9.Define electric field?

The electric field at the point P at a distance r from the point charge q is defined as the force that would be experienced by a unit positive charge placed at that point P.

10.What are the properties of equipotential surface?

(i) The work done to move a charge q between any two points A and B, W = q (VB – VA ). If the points A and B lie on the same equipotential surface, work done is zero because V_A = V_B

(ii) The electric field is normal to an equipotential surface.