magnetism and electromagnetism MCQs – Page 3

Practise focused magnetism and electromagnetism questions with marked answers for exam preparation and subject revision.

magnetism and electromagnetism Mcqs
41. The two conductors of a transmission line carry equal current I in opposite directions. The force on each conductor is________________?
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A. proportional to 7

B. proportional to distance between the conductors

C. inversely proportional to I

D. proportional to X
42. Gilbert is a unit of_______________?
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A. electromotive force

B. permittivity

C. conductance

D. magnetomotive force
43. Which of the following type of materials are not very important for engineering applications ?
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A. None of the above

B. Diamagnetic

C. Ferromagnetic

D. Paramagnetic

44. A rectangular magnet of magnetic moment M is cut into two piece of same length, the magnetic moment of each piece will be______________?
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A. M/4

B. M/2

C. 2 M

D. M

45. Out of the following statements, concerning an electric field, which statement is not true ?
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A. The electric intensity is a vector quantity

B. The electric field intensity at a point is numerically equal to the force exerted upon a charge placed at that point

C. Unit field intensity in the exertion of a force of one newton on a charge of one coulomb

D. An electric field is defined as a point in space at which an electric charge would experience a force

46. Substances which have permeability less than the permeability of free space are known as_____________?
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A. paramagnetic

B. ferromagnetic

C. bipolar

D. diamagnetic
47. Temporary magnets are used in______________?
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A. loud-speakers

B. all of the above

C. motors

D. generators

48. Two long parallel conductors carry 100 A. If the conductors are separated by 20 mm, the force per meter of length of each conductor will be_____________?
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A. 1 N

B. 10 N

C. 0.1 N

D. 100 N

49. Air gap has_________eluctance as compared to iron or steel path?
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A. little

B. lower

C. zero

D. higher

50. If a copper disc is rotated rapidly below a freely suspended magnetic needle, the magnetic needle shall start rotating with a velocity?
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A. equal to that of disc and in the same direction

B. less than that of disc and in the same direction

C. equal to that of disc and in the opposite direction

D. less than that of disc but in opposite direction

51. The Biot-savarts law is a general modification of_______________?
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A. Faradays laws

B. Kirchhoffs law

C. Amperes law

D. Lenzs law

52. A keeper is used to_____________?
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A. provide a closed path for flux

B. restore lost flux

C. amplify flux

D. change the direction of magnetic lines

53. Core of an electromagnet should have____________?
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A. low coercivity

B. high susceptibility

C. both of the above

D. none of the above

54. What is the magnitude and the direction of force per 1.1m length of a pair of conductors of a direct current linecarrying 10 amperes and spaced 100 mm apart ?
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A. 22 x 10-6 N

B. 22 x 10?5 N

C. 22 x 10?8 N

D. 22 x 10?7 N

55. Which of the following statements is correct ?
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A. The conductivity of ferrites is better than ferromagnetic materials

B. The conductivity of ferrites is very high

C. The conductivity of ferrites is same as that of ferromagnetic materials

D. The conductivity of ferromagnetic materials is better than ferrites

56. Magnetising steel is normals difficult because____________?
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A. it has low permeability

B. it has high specific gravity

C. it corrodes easily

D. it has high permeability

57. The main constituent of permalloy is_____________?
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A. chromium

B. nickel

C. cobalt

D. tungsten

58. Indicate which of the following material does not retain magnetism permanently
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A. None of the above

B. Hardened steel

C. Stainless steel

D. Soft iron
59. The electromagnet has 50 turns and a current of 1A flows through the coil. If the length of the magnet circuit is 200 mm, what is the magnetic field strength ?
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A. 2.5 AT/m

B. 2500 AT/m

C. 250 AT/m

D. 25 AT/m

60. When two ends of a circular uniform wire are joined to the terminals of a battery, the field at the center of the circle?
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A. will depend on the amount of e.m.f. applied

B. will be zero

C. will be infinite

D. will depend on the radius of the circle