# Physics Class-12th Chapter-2 “Electrostatics Potential And Capacitance” Most VVI Subjective Questions

Q.1. What is potential difference ?

Ans:- It is defined as the work done in moving a unit test charge from one point to another in the electric field.

Q.2. Define equipotential surface ?

Ans:- It is defined as the surface at which electric potential is same at all points.

Q.3. Define capacitance. Write S.I. units ?

Ans:- It is the defined as the ability of a conductor to a store charge. It is also defined as the ratio of electric charge on it to its electric potential . S.I. unit of capacitance is Farad (F).

Q.4. What do you mean by equivalent capacitor ?

Ans:- A combination of capacitors in an electric circuit can be replaced by a single capacitor that has the same capacitance as the actual combination of the capacitors. Such a capacitor is called equivalent capacitor.

Q.5. Write two properties of equipotential surface ?

Ans:- (i) The electric field lines is always perpendicular to the equipotential surface.

(ii) Two equipotential surface never intersect each other.

Q.6. Give two factors which effect capacitance of a conductor.

Ans:- (i) Material of conductor.

(ii) Cross-section area of conductor.

Q.7. Why do electric lines of force never intersect each other ? can, two equipotential surfaces intersects ?

Ans:- Two electric field lines can never intersect each other because if they intersect, then two tangents drawn at that point will represent two direction of field at that point which is not possible. Two equipotential surface cannot intersect each other because two different equipotential surface have different electric potential,  so it they intersect then the point of intersection will have two different potentials at the same point which is not possible.

Q.8. Define Dielectric strength and Relative permittivity.

Ans:- Dielectric strength – The maximum electric field that a dielectric can with stand without breakdown (for its insulating property) is called its dielectric strength.

Relative permittivity – The ratio of the strength of the applied electric field to the strength of the reduced value of the electric between the two plates is called relative permittivity.

Q.9. What is the function of second plate in a parallel plate capacitor ?

Ans:- A parallel plate capacitor of two large plane parallel conducting metal plates separated by a small distance. The second plate acts as a neighbouring conductor due to which the potential of first plate is reduced, keeping it same size due to which the capacitance increase.

Q.10. In what form is the energy stored in a charged capacitor ?

Ans:- The energy is stored in the form of electric field between the two plates that is in the form of electric energy in a charged capacitor.