JEE Main - Electric field and field lines Online Test (MCQ Quiz)

1. What is the unit of electric field strength?

A) Newton per Coulomb (N/C) B) Volt per meter (V/m) C) Ampere per meter (A/m) D) Joule per Coulomb (J/C)

2. Electric field lines originate from which type of charge?

A) Negative charge B) Positive charge C) Neutral charge D) Both positive and negative charges

3. Electric field lines terminate on which type of charge?

A) Positive charge B) Neutral charge C) Negative charge D) Induced charge

4. Which property of electric field lines indicates the direction of the electric field at a point?

A) Density of lines B) Number of lines C) Direction of the tangent to the line D) Spacing between lines

5. What does the density of electric field lines represent?

A) The direction of the electric field B) The magnitude of the electric field C) The polarity of the charge D) The total charge enclosed

6. Can electric field lines intersect each other?

A) Yes, they can intersect at any point B) Yes, but only if the charges are of opposite sign C) No, electric field lines never intersect D) Yes, they can intersect if there is a neutral point

7. What is the electric field at an infinite distance from a point charge?

A) Infinite B) Finite and non-zero C) Zero D) Undetermined

8. For a positive point charge, electric field lines are directed:

A) Radially inwards B) Radially outwards C) Tangentially D) Along the axis of symmetry

9. For a negative point charge, electric field lines are directed:

A) Radially outwards B) Tangentially C) Along the axis of symmetry D) Radially inwards

10. What is the electric field at the center of an electric dipole?

A) Maximum B) Zero C) Non-zero but finite D) Infinite

11. Electric field lines are parallel and equally spaced in the field of:

A) A point charge B) An electric dipole C) An infinite line charge D) A uniformly charged infinite plane

12. Electric field lines are perpendicular to the surface of a conductor in electrostatic equilibrium.

A) Always true B) True only for charged conductors C) True only for conductors in a uniform external field D) Never true

13. What is the electric field inside a hollow charged conductor?

A) Maximum at the center B) Non-zero but constant C) Zero D) Equal to the field outside

14. The electric field lines due to a system of two identical positive charges are:

A) Converging at infinity B) Diverging from a point between the charges C) Repelling each other D) Showing a neutral point at infinity

15. The electric field lines due to a system of two equal and opposite charges (a dipole) are:

A) Straight lines B) Closed loops C) Elliptical or curved lines starting from positive and ending on negative D) Parallel lines

16. Which of the following statements about electric field lines is incorrect?

A) They are continuous curves. B) They start from positive charges and end on negative charges. C) They can form closed loops. D) The tangent to a field line at any point gives the direction of the electric field at that point.

17. What is the net electric flux through a closed surface enclosing a net charge Q?

A) Q / ε₀ B) Q * ε₀ C) Zero D) Dependent on the shape of the surface

18. If the number of electric field lines passing through a surface is N, and the surface area is A, what is the approximate electric field strength if the lines are perpendicular to the surface?

A) N / A B) A / N C) N * A D) N + A

19. Consider a large sheet of charge with uniform surface charge density σ. The electric field lines near the sheet are:

A) Curved B) Parallel and perpendicular to the sheet C) Diverging from the sheet D) Converging towards the sheet

20. What is the electric field at a distance r from an infinitely long uniformly charged wire with linear charge density λ?

A) Proportional to 1/r B) Proportional to 1/r² C) Proportional to r D) Constant

21. Electric field lines are drawn such that the number of lines per unit area perpendicular to the lines is proportional to:

A) The potential difference B) The charge density C) The electric field strength D) The permittivity of the medium

22. If two charges +q and -q are placed at a distance d apart, the electric field at the midpoint of the line joining them is:

A) Zero B) Maximum C) Minimum but non-zero D) Directed towards the negative charge

23. What happens to the electric field lines when they enter a conducting medium?

A) They become denser B) They stop abruptly C) They terminate on the surface of the conductor D) They pass through the conductor

24. Which of the following represents the electric field of a dipole?

A) Radial lines originating from a single point B) Parallel lines C) A pattern of curved lines originating from the positive charge and terminating on the negative charge D) Concentric circles

25. The electric field is conservative. This means that the work done by the electric field in moving a charge between two points is:

A) Infinite B) Zero C) Dependent on the path taken D) Equal to the potential difference

26. For a uniformly charged sphere, the electric field outside the sphere behaves as if the charge were concentrated at:

A) The center of the sphere B) The surface of the sphere C) A point at infinity D) Any point on the surface

27. What is the electric field at the surface of a charged conductor?

A) Zero B) Maximum C) σ/ε₀, where σ is the surface charge density D) σ*ε₀

28. Electric field lines are used to visualize:

A) Electric potential B) Electric current C) Electric field D) Electric charge

29. In a region of uniform electric field, electric field lines are:

A) Converging B) Diverging C) Parallel and equally spaced D) Curved

30. Which of the following statements about electric field lines is true?

A) They represent the path of a positive test charge. B) They indicate the direction of the force on a positive test charge. C) They are always closed loops. D) Their density is inversely proportional to the electric field strength.

31. The electric field strength is given by E = F/q. Here, q is:

A) The source charge creating the field B) A positive test charge C) A negative test charge D) Any arbitrary charge

32. Electric field lines are drawn to be perpendicular to the equipotential surfaces. This implies:

A) Electric field is parallel to equipotential surfaces. B) Work done in moving a charge along an equipotential surface is zero. C) Electric field is zero on equipotential surfaces. D) Electric potential is zero on equipotential surfaces.

33. Consider a point charge q. The electric field lines are denser closer to the charge. This illustrates that the electric field strength:

A) Is constant everywhere B) Decreases with distance from the charge C) Increases with distance from the charge D) Is zero at the charge

34. What is the electric field at the center of a uniformly charged ring?

A) Maximum B) Non-zero and directed along the axis C) Zero D) Infinite

35. The electric field lines for a system of two identical negative charges:

A) Converge to a point between the charges B) Diverge from a point between the charges C) Repel each other D) Show neutral points at infinity

36. If the electric field is E, and a small area element is dA, the electric flux through this element is given by:

A) E * dA B) E / dA C) E . dA D) E + dA

37. What is the electric field at the surface of a charged conductor in vacuum?

A) Zero B) σ / (2ε₀) C) σ / ε₀ D) 2σ / ε₀

38. Electric field lines can never cross each other because:

A) Charges would repel B) The electric field at a point must have a unique direction C) The net charge would be zero D) The medium prevents crossing

39. In the case of an electric dipole, the electric field lines are:

A) Straight lines radiating outwards B) Closed loops C) Curved lines starting from the positive charge and ending on the negative charge D) Parallel lines

40. The electric field strength is proportional to the:

A) Number of field lines B) Density of field lines C) Spacing between field lines D) Area enclosed by field lines

41. What is the electric field at the center of a uniformly charged solid sphere?

A) Zero B) Maximum C) Non-zero and finite D) Infinite

42. If the electric field lines are diverging from a point, it indicates the presence of a:

A) Negative charge B) Positive charge C) Neutral point D) Charged conductor

43. Electric field lines are perpendicular to the surface of a conductor because:

A) The electric field inside a conductor is zero B) Charges reside on the surface of a conductor C) There is no electric field parallel to the surface of a conductor in equilibrium D) The conductor is an insulator

44. What is the unit of electric flux?

A) Newton per meter squared (N/m²) B) Volt-meter (V·m) C) Newton-meter squared per Coulomb (Nm²/C) D) Coulomb per meter squared (C/m²)

45. The electric field lines are closer together where the electric field is:

A) Weak B) Strong C) Uniform D) Zero

46. Which of the following correctly describes the electric field lines from a system of one positive and one negative charge of equal magnitude?

A) They start from the positive charge and end on the negative charge, forming curved paths. B) They are parallel lines moving from positive to negative. C) They are concentric circles around the positive charge. D) They diverge outwards from both charges.

47. The electric field strength at a distance r from a point charge Q is proportional to:

A) 1/r B) 1/r² C) r D) r²

48. Electric field lines map out the direction and magnitude of the electric field. Which statement is true?

A) The density of lines represents the direction of the field. B) The number of lines originating from a positive charge is proportional to the magnitude of the charge. C) Field lines can start or end at any arbitrary point. D) Field lines represent the path of electrons.

49. What is the electric field at the surface of a charged conductor if it is placed in a dielectric medium of relative permittivity εr?

A) σ / ε₀ B) σ / (ε₀εr) C) σε₀εr D) σε₀ / εr

50. The electric field lines are always directed from regions of higher electric potential to regions of lower electric potential. This means:

A) Electric field is parallel to equipotential lines. B) Electric field is perpendicular to equipotential lines. C) Electric field is zero where potential is highest. D) Electric field is strongest where potential is constant.

Electric field and field lines - Online Test

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