Electrical Engineering Materials MCQ PDF Download

42. Diamagnetic materials possess

(a) permanent dipoles.
(b) induced dipoles.
(c) both permanent and induced dipoles.
(d) no dipoles.

43. Above the Curie temperature, ferromagnetic materials behave like

(a) paramagnetic.
(b) diamagnetic.
(c) anti-ferromagnetic.
(d) ferrimagnetic.

44. The phenomenon by which a ferromagnetic material is magnetized to its final state by a magnetic field is attributed to

(a) eddy currents and magnetic viscosity.
(b) magnetic viscosity and hysteresis.
(c) hysteresis and eddy currents.
(d) ageing and magnetic viscosity.

45. The magnetic domains, during the process of magnetization of ferromagnetic materials,

(a) only expand.
(b) rotate first and then expand.
(c) expand first and then rotate.
(d) neither rotate nor expand.

46. Consider the following statements referring to the magnetization:

1. In solenoid magnetization is due to a surface current distribution.
2. Magnetization has its origin in circulating current.
3. The solenoid dipole is represented by an infinitesimal current – loop.
4. The magnetization is entirely solenoidal and divergent.

Which of the above statements is/are correct?
(a) 1, 2 and 3 only.
(b) 2, 3 and 4 only.
(c) 3 only.
(d) 1, 2, 3 and 4.

47. A ferromagnetic material exhibits different characteristics above and below the

(a) Joule’s temperature.
(b) Faraday temperature.
(c) Curie temperature.
(d) Neel temperature.

48. A large value of the exchange interaction energy in a ferromagnetic material implies

(a) large saturation magnetization.
(b) high Curie temperature.
(c) high melting point.
(d) large diamagnetic susceptibility.

49. Materials which lack permanent magnetic dipoles are known as

(a) paramagnetic.
(b) diamagnetic.
(c) ferromagnetic.
(d) ferrimagnetic.

50. Metallic copper is a

(a) paramagnetic substance.
(b) diamagnetic substance.
(c) ferromagnetic substance.
(d) ferrimagnetic substance.

51. Susceptibility of a diamagnetic material is

1. negative.
2. positive.
3. dependent on the temperature.
4. independent of the temperature.

Select the correct answer using the codes given below:
(a) 1 and 3.
(b) 2 and 4.
(c) 1 and 4.
(d) 2 and 3.

52. Consider the following statements about diamagnetic materials and diamagnetism:

1. The materials have negative magnetic susceptibility.
2. At very low temperatures, diamagnetic materials are converted into paramagnetic materials.

Which of the statements given above is/are correct?
(a) 1 only.
(b) 2 only.
(c) Both 1 and 2.
(d) Neither 1 nor 2.

53. Which of the following statement(s) is/are correct ?

1. Ferromagnetic substances have very large negative values of susceptibility.
2. Diamagnetic substances have very small negative values of susceptibility.
3. Paramagnetic substances have very small positive values of susceptibility. . The permeability of diamagnetic substances is slightly greater than unity.

Select the correct answer using the codes given below
(a) 1 and 4.
(b) 2 and 3.
(c) 3 and 4.
(d) 4 alone.

55. Interaction between the neighboring dipoles is negligible in case of………….materials.

(a) paramagnetic
(b) diamagnetic
(c) ferromagnetic
(d) ferrimagnetic

56. In…………materials the atomic magnetic moments are oriented, in a random fashion, in a solid.

(a) diamagnetic
(b) paramagnetic
(c) ferromagnetic
(d) none of these

57. A material with unequal, antiparallel atomic magnetic moments is called the………..material.

(a) ferrimagnetic
(b) ferromagnetic
(c) antiferromagnetic
(d) none of these

58. Ferrimagnetic materials are generally used as

(a) conductors.
(b) insulators.
(c) semiconductors.
(d) resistors.

59. Ferrites are………….materials.

(a) ferromagnetic
(b) ferrimagnetic
(c) diamagnetic
(d) antiferromagnetic

60. The resistivity of ferrites is……….that of ferromagnetic materials.

(a) less than
(b) equal to
(c) slightly more than
(d) very much higher than

61. Ferrites are………..materials.

(a) hard
(b) brittle
(c) not easily machinable
(d) hard, brittle and not easily machinable

62. Dielectric loss in ferrites is

(a) zero.
(b) very low.
(c) low.
(d) very high.

63. Magnetically saturated ferrite

(a) interacts with electromagnetic waves.
(b) produces large hysteresis.
(c) produces low eddy currents.
(d) all of the above.

64. When the temperature of a magnetic material is raised above the Curie point, it becomes

(a) diamagnetic.
(b) paramagnetic.
(c) ferromagnetic.
(d) ferrimagnetic.

65. Consider the following statements : In the case of paramagnetic materials, there

1. is no permanent dipole moment.
2. are permanent dipole moments.
3. is no alignment of dipoles in the absence of magnetic field.
4. is no interaction among the dipoles.

Which of these statement(s) is/are correct?
(a) 1 alone.
(b) 3 and 4.
(c) 2 and 4.
(d) 2, 3 and 4.

66. Which of the following exhibit hysteresis?

(a) Ferromagnetic materials only.
(b) Ferroelectric materials only.
(c) Ferrielectric materials only.
(d) Both ferroelectric and ferrielectric materials.

67. What are the materials which exhibit electric polarization even in the absence of an applied electric field called?

(a) Ferromagnetic.
(b) Paramagnetic.
(c) Ferroelectric.
(d) Anti-ferroelectric.

68. The property characteristic of ferroelectric materials is

(a) dielectric relaxation.
(b) dielectric breakdown.
(c) spontaneous polarization.
(d) spontaneous magnetization.

69. Which one of the following is not a characteristic of a ferroelectric material?

(a) High dielectric constant.
(b) No hysteresis.
(c) Ferroelectric characteristic only above the Curie point.
(d) Electric dipole moment.

70. If the centre of gravity of the positive and negative charges in a body do not coincide in the absence of an applied electric field, the substance has an electric dipole moment and is said to be spontaneously polarized. Such a substance is known as

(a) ferroelectric.
(b) dielectric.
(c) insulator.
(d) ferromagnetic.

71. A ferroelectric material contains small regions which are polarized in different directions even in the…………of an electric field.

(a) presence
(b) absence
(c) either of the above
(d) none of the above

72. Which one of the following is a ferroelectric material ?

(a) Stainless steel.
(b) Brass.
(c) Barium nitrate.
(d) Wrought iron.

73. Which one of the following is not a ferroelectric material ?

(a) Y-alloy.
(b) Rochelle salt.
(c) Lead zirconate.
(d) Boron nitride.

74. Materials having high dielectric constant, which is nonlinear, are called the

(a) hard dielectrics.
(b) super dielectrics.
(c) ferroelectric materials.
(d) none of the above.

75. Ferroelectric materials are characterized by

(a) very high degree of polarization.
(b) a sharp dependence of polarization on temperature.
(c) nonlinear dependence of the charge on the applied voltage.
(d) all of the above.

76. Potassium dihydrogen phosphate has………….Curie points.

(a) negative
(b) positive
(c) two
(d) none of these

77. The………….polarization vanishes at Curie temperature of the material.

(a) dipolar
(b) spontaneous
(c) ionic
(d) polar

78. The temperature beyond which ferroelectric materials lose their ferroelectric properties is called the temperature.

(a) critical
(b) inversion
(c) Curie
(d) absolute

79. The ferroelectric materials, above the Curie temperature lose ferro-electric properties and become ordinary………….materials.

(a) insulating
(b) dielectric
(c) ferromagnetic
(d) super conducting

78. Barium titanate is…………material.

(a) ferroelectric
(b) piezoelectric
(c) ferromagnetic
(d) semiconductor
(e) both ferroelectric and piezoelectric

79. Quartz and BaTiO₃ exhibit which of the following properties?

(a) Magnetostriction.
(b) Ferromagnetism.
(c) Piezoelectricity.
(d) Ferroelectricity.

80. The dielectric strength of ferroelectric materials depends to a large extent on

(a) frequency of applied voltage.
(b) intensity of electric field.
(c) presence of magnetic materials in the vicinity.
(d) hysteresis loop area for the material.