# Objective Questions on Static Electric Field

1. Electric field intensity ( E ) at any point in an electric field is equal to

The total electric field at any point is equal to the vector sum of the separate electric fields that each point charge would create in the absence of the others. That is,

The electric field is nothing but the potential gradient of that particular point.

2. The lines of force due to charged particles are

The right hand rule can be used to determine the direction of the force on charged particles. It looks always curved lines.

3. The ability of charged bodies to exert force on one another is attributed to the existence of

The movement of electrons only can create the force on charge. And it would exert force on another one nearby charge also.

4. An electric field line and an equipotential surface are

For parallel conducting plates like those in a capacitor, the electric field lines are perpendicular to the plates hence they are parallel to each other and the equipotential lines are parallel to the plates.

5. Which of following is not a vector?

An electric field E is related with the electric potential φ is defined through the expression E = − ∇φ. Hence, it is not a vector. It is a scalar product.

6. The ratio of electric flux density to electric field intensity is called ......... of medium

Because, ε = D / E Here, D is electric flux density and E is electric field intensity.

7. The value of E within the field due to a point charge can be found with help of

Coulomb’s law is only one law that deals with electric charge. The Faraday’s Law and Lenz Law are deals with electromagnetic systems and Kirchhoff’s Law is deals with electric circuits.

8. To prevent the generation of static charges on rubber or flat leather

Static electricity is caused by the movement of electrons when two dissimilar substances are separated. But, the conductive dressing system would not allow them to separate with each other.

9. The electric field at a point situated at a distance d from straight charged conductor is

The electric field at a point if the conductor length is infinite is as follows;

Hence, the electric field is inversely proportional to distance d.

10. The presence of an uncharged conductor near a charged one increases the

The presence of an uncharged conductor near a charged conductor would make a condenser or a capacitor. Whenever, the charge increases then the capacity of the charged conductor would also increase.

11. Permittivity is expressed in

The electrical capacitance that is measured in farads is the only electrical property of the free space between two parallel plates of cross-section 'A' in m2 separated by distance 'd' in m. Thus, the expression of capacitor is as follows;

Hence, the unit is Farad per meter.

12. Which field is associated with the capacitor?

Capacitor has dielectric medium with it. In dielectric medium, there would be a chance to create an electric field.

13. The electrostatic force between two charges of one coulomb each and placed at a distance of 0.5 m will be

14. The potential gradient across the material of low permittivity is ______________ than across the material of high permittivity.

We know that the force development by a charged particle is F = Q / (4πεd2).The electric force F and electric field E are related as F = Q × E. Therefore, if we apply this relation with first expression, we would get E = 1 / (4πεd2). Hence, for low permittivity the potential gradient is greater than the high permittivity.

15. Which of the following expression is correct for electric field strength?

In a dielectric material, the presence of an electric field E causes the bound charges in the material to slightly separate. Hence, the electric displacement field D is defined as D = E × ε.

16. An equipotential surface is one which has all points at _____________ potential.

Equipotential means same potential everywhere.

17. XEROX machine is working on

The process is to spray the electric charge upon the semiconductor surface, and flash the image which would copy and the ink would permanently stick due to the hot pressure from the semiconductor surface.

18. The number of Faraday tubes of flux passing through a surface in an electric field is called

The tubes of flux passing per unit area through a medium are supposed to be the electric displacement of that that dielectric medium. In this case, they referred to as the electric flux.

19. Electric intensity at any point in an electric field is equal to the ___________ at that point.

The total electric field at any point is equal to the vector sum of the separate electric fields that each point charge would create in the absence of the others. That is,

The electric field is nothing but the potential gradient of that particular point.

20. The unit of electric field intensity is

Electric field intensity is the force experienced by a unit positive charge by another one charge. Hence, E = F / Q . Therefore, the unit of electric field is Newton per Coulomb.