Electric Charges and Fields – MCQ Part 1 CBSE Class 12 Physics

1. Charge is the property associated with matter due to which it produces and experiences

(a) electric effects only

(b) magnetic effects only

(d) None of these

2. Charge is

(a) transferable (b) associated with mass

3. A body is positively charged, it implies that

(a) there is only positive charge in the body.

(b) there is positive as well as negative charge in the body but the positive charge is more than negative charge

(d) negative charge is displaced from its position

4. On rubbing, when one body gets positively charged and other negatively charged, the electrons transferred from positively charged body to negatively charged body are

(a) valence electrons only

(b) electrons of inner shells

(d) yet to be established

5. Which of the following is the best insulator?

(a) Carbon (b) Paper

6. If a body is negatively charged, then it has

(a) excess of electrons (b) excess of protons

7. When a body is charged by induction, then the body

(a) becomes neutral

(b) does not lose any charge

(d) loses part of the charge on it

8. On charging by conduction, mass of a body may

(a) increase (b) decreases

9. Quantisation of charge implies

(a) charge cannot be destroyed

(b) charge exists on particles

(d) charge, which is a fraction of a coulomb is not possible.

10. If an object possesses an electric charge, it is said to be electrified or … A … When it has no charge, it is said to be … B … Here, A and B refer to

(a) charged, neutral (b) neutral, charged

11. A positively charged rod is brought near an uncharged conductor. If the rod is then suddenly withdrawn, the charge left on the conductor will be

(a) positive (b) negative

12. Two spheres A and B of exactly same mass are given equal positive and negative charges respectively. Their masses after charging

(a) remains unaffected (b) mass of A > mass of B

13. When a comb rubbed with dry hair attracts pieces of paper.

This is because the

(a) comb polarizes the piece of paper

(b) comb induces a net dipole moment opposite to the direction of field

(d) comb induces a net dipole moment perpendicular to the direction of field

14. When some charge is transferred to …A… it readily gets distributed over the entire surface of … A… If some charge is put on … B…, it stays at the same place.

Here, A and B refer to

(a) insulator, conductor (b) conductor, insulator

15. Quantisation of charge was experimentally demonstrated by

(a) Einstein’s photoelectric effect

(b) Frank-Hertz experiment

(d) Millikan’s oil drop experiment

16. In annihilation process, in which an electron and a positron transform into two gamma rays, which property of electric charge is displayed?

(a) Additivity of charge

(b) Quantisation of charge

(d) Attraction and repulsion

17. The law, governing the force between electric charges is known as

(a) Ampere’s law (b) Ohm’s law

18. The value of electric permittivity of free space is

(a) 9 × 10⁹ NC² / m²

(b) 8.85 × 10^–12Nm² / C²sec

(d) 9 × 10⁹ C²/ Nm²

19. Coulomb’s law is true for

(a) atomic distances (= 10^–11 m)

(b) nuclear distances (= 10^–15 m)

(d) all the distances

20. What happens when some charge is placed on a soap bubble?

(a) Its radius decreases (b) Its radius increases

21. Two point charges + Q and + q are separated by a certain distance. If + Q > + q then in between the charges the electric field is zero at a point

(a) closer to + Q

(b) closer to + q

(d) no where on the line segment joining + Q and + q.

22. An electric field can deflect

(a) neutrons (b) X-rays

23. The unit of electric field is not equivalent to

(a) N / C (b) J / C

24. If an electron has an initial velocity in a direction different from that of an electric field, the path of the electron is

(a) a straight line (b) a circle

25. A charged particle is free to move in an electric field. It will travel

(a) always along a line of force

(b) along a line of force, if its initial velocity is zero

(d) none of the above

26. If a linear isotropic dielectric is placed in an electric field of strength E, then the polarization P is

(a) independent of E

(b) inversely proportional to E

(d) directly proportional to E

27. A point charge is kept at the centre of metallic insulated spherical shell. Then

(a) electric field outside the sphere is zero

(b) electric field inside the sphere is zero

(d) electric potential inside the sphere is zero

28. If one penetrates a uniformly charged spherical cloud, electric field strength

(a) decreases directly as the distance from the centre

(b) increases directly as the distance from the centre

(d) None of these

29. Electric lines of force about a negative point charge are

(a) circular anticlockwise

(b) circular clockwise

(d) radial, outwards

30. Electric lines of force

(a) exist everywhere

(b) exist only in the immediate vicinity of electric charges

(d) are imaginary

31. Positive electric flux indicates that electric lines of force are directed

(a) outwards (b) inwards

32. The S.I. unit of electric flux is

(a) weber (b) newton per coulomb

33. If the flux of the electric field through a closed surface is zero, then

(a) the electric field must be zero everywhere on the surface

(b) the electric field may not be zero everywhere on the surface

(d) the charge in the vicinity of the surface must be zero

34. Electric flux over a surface in an electric field may be

(a) positive (b) negative

35. If the electric flux entering and leaving an enclosed surface respectively is I₁ and I₂, the electric charge inside the surface will be

(a) (ϕ₂+ ϕ₂) x ɛ₀ (b) (ϕ₂– ϕ₂) x ɛ₀

36. For distance far away from centre of dipole the change in magnitude of electric field with change in distance from the centre of dipole is

(a) zero.

(b) same in equatorial plane as well as axis of dipole.

(d) more in case of axis of dipole as compared to equatorial plane of dipole.

37. A region surrounding a stationary electric dipoles has

(a) magnetic field only

(b) electric field only

(d) no electric and magnetic fields

38. The electric field at a point on equatorial line of a dipole and direction of the dipole moment

(a) will be parallel

(b) will be in opposite direction

(d) are not related

39. Debye is the unit of

(a) electric flux (b) electric dipole moment

40. An electric dipole will experience a net force when it is placed in

(a) a uniform electric field

(b) a non-uniform electric field

(d) None of these

41. An electric dipole is kept in a non-uniform electric field. It experiences

(a) a force and a torque

(b) a force but not a torque

(d) neither a force nor a torque

42. The formation of a dipole is due to two equal and dissimilar point charges placed at a

(a) short distance (b) long distance

44. If E_a be the electric field strength of a short dipole at a point on its axial line and E_e that on the equatorial line at the same distance, then

(a) E_e = 2E_a

(b) E_a = 2E_e

(d) None of the above

45. When an electric dipole P is placed in a uniform electric field E, then at what angle between P and E the value of torque will be maximum?

(a) 90° (b) 0°

46. An electric dipole is placed at an angle of 30° to a non-uniform electric field. The dipole will experience

(a) a translational force only in the direction of the field

(b) a translational force only in the direction normal to the direction of the field

(d) a torque only

47. An electric dipole is placed at the centre of a sphere then

(a) the flux of the electric field through the sphere is not zero.

(b) the electric field is zero at every point of the sphere.

(d) the electric field is zero on a circle on the sphere.

49. An electric dipole has a pair of equal and opposite point charges q and –q separated by a distance 2x. The axis of the dipole is

(a) from positive charge to negative charge

(b) from negative charge to positive charge

(d) Perpendicular to the line joining the two charges drawn at the centre and pointing downward direction

51. The Gaussian surface

(a) can pass through a continuous charge distribution.

(b) cannot pass through a continuous charge distribution.

(d) can pass through a continuous charge distribution as well as any system of discrete charges.

52. Gauss’s law is valid for

(a) any closed surface

(b) only regular close surfaces

(d) only irregular open surfaces

54. The electric field due to an infinitely long straight uniformly charged wire at a distance r is directly proportional to

(a) r (b) r²

56. The electric field inside a spherical shell of uniform surface charge density is

(a) zero

(b) constant different from zero

(d) None of the above

58. A hollow sphere of charge does not have electric field at

(a) outer point (b) interior point

59. Charge motion within the Gaussian surface gives changing physical quantity

(a) electric field (b) electric flux

60. Gauss’s law is true only if force due to a charge varies as

(a) r^–1 (b) r^–2

61. What about Gauss’s theorem is not incorrect?

(a) It can be derived by using Coulomb’s Law

(b) It is valid for conservative field obeys inverse square root law

(d) Both (a) & (b)

62. Study of charges, by scientists, concludes that

I. there are two kinds of electric charges.

II. bodies like plastic, fur acquire elecrtic charge on rubbing.

III. like charges attract, unlike charges repel each other.

IV. the property which differentiates two kinds of charges is called the polarity of the charge.

Which of the above statements is incorrect?

(a) Only I (b) Only II

63. Which of the following statements is incorrect?

I. The charge q on a body is always given by q = ne, where n is any integer, positive or negative.

II. By convention, the charge on an electron is taken to be negative.

III. The fact that electric charge is always an integral multiple of e is termed as quantisation of charge.

IV. The quatisation of charge was experimentally demonstrated by Newton in 1912.

(a) Only I (b) Only II

64. Select the correct statements Coulomb’s law correctly describes the electric force that

I. binds the electrons of an atom to its nucleus

II. binds the protons and neutrons in the nucleus of an atom

III. binds atoms together to form molecules

(a) I and II (b) I and III

65. Select the correct statements from the following

I. Inside a charged or neutral conductor, electrostatic field is zero

II. The electrostatic field at the surface of the charged conductor must be tangential to the surface at any point

III. There is no net charge at any point inside the conductor

(a) I and II (b) I and III

66. In a uniform electric field E a charge +q having negligible mass is released at a point. Which of the following statements are correct?

I. Velocity increases with time.

II. A force acts on it in the direction of electric field.

III. Its momentum changes with time.

(a) I and II (b) II and III

67. Field due to multiple charges at a point is found by using

I. superposition principle.

II. Coulomb’s law.

III. law of conservation of charges.

(a) I and II (b) II and III

68. Select the incorrect statements about electric field lines.

I. Two electric field lines can never cross each other.

II. They start from positive charge and end at negative charge.

III. Electric field lines form closed loops.

(a) I and II (b) I and III

70. Select the incorrect statements from the following.

I. Polar molecules have permanent electric dipole moment.

II. CO₂ molecule is a polar molecule.

III. H₂O is a non-polar molecule.

(a) II and III (b) I and II

71. Select the correct statements from the following.

I. The electric field due to a charge outside the Gaussian surface contributes zero net flux through the surface.

II. Total flux linked with a closed body, not enclosing any charge will be zero.

III. Total electric flux, if a dipole is enclosed by a surface is zero.

(a) I and II (b) II and III

ANSWER KEY

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Electric Charges and Fields – MCQ Part 1 CBSE Class 12 Physics

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