Top 300 Electricity and Magnetism Questions & Answers

In this article, we shared the top 300 electricity and magnetism objective questions and answers for instrumentation, electrical, and electronics engineering students.

Electricity and Magnetism Questions

Electricity and Magnetism Questions & Answers

The below list provides all the multiple-choice questions (MCQ) related to electricity and magnetism.

Answers are available at the bottom of the article.

1. Who demonstrated the theory of electromagnetic induction in 1831?

A)James Clerk Maxwell
B)Charles Coulomb
C)Andre Ampere
D)Michael Faraday

2. What solid has no defined crystal structure except perhaps in the arrangement of the nearest neighboring atoms or ions?

A)Amorphous
B)Poly- amorphous
C)Polycrystalline
D)Crystalline

3. The ability of a material to conduct magnetic flux through it.

A)Permittivity
B)Reluctivity
C)Conductivity
D)Permeability

4. If a 20 V potential is applied across a relay coil with 50 turns having​​ of resistance, the total magnetomotive producing magnetic flux in the circuit is

A)1000 A.t
B)50 T
C)10 Wb
D)1000 A t/m

5. Which of the following materials has the least hysteresis loop area?

A)soft iron
B)wrought iron
C)hard steel
D)silicon steel

6. The lagging effect between flux density of the material and the magnetizing force applied

A)Hysteresis
B)Reluctance
C)Eddy current
D)Permeance

7. Which of the following has the highest permeability?

A)Soft iron
B)Steel
C)Permalloy
D)Air

8. Who demonstrated that there are magnetic effects around every current-carrying conductor and that current-carrying conductors can attract and repel each other just like magnets?

A)Luigi Galvani
B)Hans Christian Oersted
C)Charles Coulomb
D)Andre Ampere

9. If the right handed bottle-opener cork screw is assumed to be along the conductor so as to advance in the direction of current flow, the motion of its handle will indicate the direction of magnetic flux produced around the conductor.

This is known as

A)End rule
B)Cork screw rule
C)Left hand rule
D)Right hand rule

10. The science of adapting electronics to aerospace flight.

A)Aerotronics
B)Astrionics
C)Avionics
D)Aerodynamics

11. Ohm’s law cannot be applied to which material?

A)Aluminum
B)Silver
C)Silicon carbide
D)Copper

12. If the number of valence electrons of an atom is less than 4, then the substance is probably

A)a non-metal
B)a metal
C)a semiconductor
D)an insulator

13. Theory of ferromagnetic phenomena which assumes each atom is a permanent magnet which can turn freely about its center under the influence of applied field and other magnets.

A)Oersted’s ferromagnetism theory
B)Ampere’s circuital law
C)Ewing’s theory of ferromagnetism
D)Maxwell’s magnetic theory

14. The magnetic field around the conductor is determined by the

A)Resistance divided by the current
B)Current divided by the resistance
C)Size of the conductor
D)Amount of current

15. Flux linkages equals

A)Flux times number of turns times length of core
B)Flux times number of turns
C)Flux times area of core
D)Flux times number of turns times area of core

16. Why is it that the magnitude of magnetomotive force required for air gap is much ​ greater than that required for iron part of a magnetic circuit?

A)Because air has the lowest relative permeability
B)Because air is a gas
C)Because air is a conductor of magnetic flux
D)Because air has the highest relative permeability

17. Formed when there exist distant electronic interactions between (opposite) charges present in the neighboring atoms or molecules.

A)Covalent bond
B)Van der Waals bond
C)Ionic bond
D)Metallic bond

18. The ratio between the intensity of magnetization produced in a substance to the magnetizing force producing it

A)Magnetic Reluctivity
B)Magnetic conductivity
C)Magnetic susceptibility
D)Magnetic Resistivity

19. Two similar poles, each 1Wb, placed 1 m apart in air will experience a repulsive force of

A)8 ×​ 1012 N​
B)63000 N
C)796 kN
D)63 ×​​ 10-13 N​

20. What is the practical unit of electrical energy?

A)Megawat-hour
B)Watt
C)Kilowatt-second
D)Kilowatt-hour

21. Electric potential is a ​ ​_____ quantity.

A)scalar
B)phasor
C)vector
D)variable

22. The space outside the magnet where its pole have a force of attraction or repulsion on a magnetic pole is called

A)Electromagnetic field
B)Magnetic field
C)Free Space Field
D)Electric field

23. When the relative permeability of a material is slightly more than 1, ​ it ​ is called ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ material.

A)ferromagnetic
B)non-magnetic
C)diamagnetic
D)paramagnetic

24. Define as that pole which when placed in air from a similar and equal pole repels it with a force of newtons

A)North pole
B)South pole
C)Unit pole
D)Magnetic pole

25. How much is the flux in Weber in the above problem?

A)2 x​​ 103
B)2 x​​ 10-3
C)2 x​​ 10-5
D)2 x​​ 105

26. When a current carrying conductor is placed in a magnetic field, the maximum force will act on the conductor when the conductor is at an angle of _____ to the magnetic field.

A)​​30 deg C
B)​​​​90 deg C
C)​​​​60 deg C
D)​​​​45 deg C

27. Who discovered that a current-carrying conductor would move when placed in a magnetic field?

A)Michael Faraday
B)Gustav Robert Kirchhoff
C)Andre Ampere
D)Hans Christian Oersted

28. The simplest type of atom to exist is the _____ atom.

A)Hydrogen
B)Boron
C)Oxygen
D)Helium

29. If the value of​ ​α25 a conductor is 1/255 per​ oC​ , then the value of​ α20​ is

A)1/230 per​​ oC
B)1/300 per​​ oC
C)1/250 per​​ oC
D)1/260 per​ oC​

30. The resistivity of a conductor _____ with an increase in temperature.

A)none of the answers
B)decreases
C)becomes zero
D)increases

31. Refers to the non-metallic materials that have the ferromagnetic properties of iron.

A)Diamagnetic
B)Ferromagnetic
C)Paramagnetic
D)Ferrites

32. A current if flowing east along a power line. if the earth’s field is neglected, the direction of the magnetic field below it is

A)West
B)North
C)South
D)East

33. What is the typical saturation flux density for most magnetic materials?

A)​​1 Wb/m2
B)​​​​4 Wb/m2
C)5 Wb/m2
D)2 Wb/m2

34. The uncharged particles which have no effect on its atomic charge.

A)Neutrons
B)Nucleons
C)Protons
D)Electrons

35. What principle states that each electron in an atom must have a different set of quantum numbers?

A)Quantum principle
B)Inclusion principle
C)Electron principle
D)Exclusion principle

36. A magnetic circuit carries a flux θi ​​in the iron part and a flux θg ​​in the air gap. What is the leakage coefficient?

A)​​θi + θg
B)​​​​θi x θg
C)​​​​θi / θg
D)​​​​​​θg / θi

37. Which of the following materials has the highest dielectric strength?

A)Mica
B)Glass
C)Oiled paper
D)Air

38. Back emf refers to the

A)Current equal to the applied emf
B)Current opposing the applied emf
C)Opposing emf
D)Voltage opposing the applied emf

39. One weber of flux is equal to _____ magnetic lines of force.

A)​​1010
B)​​​​108
C)​​​​107
D)​​​​106

40. Referred to as the specific reluctance of a material

A)Resistivity
B)Conductivity
C)Permeability
D)Reluctivity

41. Electronic current in a wire is the flow of _____ electrons.

A)loose
B)valence
C)bound
D)free

42. This paper does not exhibit electricity because it contains the same number of

A)neutrons and electrons
B)atoms
C)protons and electrons
D)neutrons and positrons

43. Electric field intensity is measured in

A)Newton/meter
B)Amperes/meter
C)Newton-meter
D)volts/meter

44. Three charges of +5 C, -6 C and +9 C are placed inside a sphere. What is the total flux passing through the surface of sphere?

A)8 C
B)-6 C
C)14 C
D)20 C

45. Hysteresis refers to the ​_____ magnetizing force applied.

A)Leading effect
B)Lagging effect
C)Ratio
D)Equality

46. The reluctance of a magnetic circuit varies with

A)length × area
B)length + area
C)area ÷ length
D)length ÷ area

47. A law establishing the fact that the algebraic su of the rises and drops of the mmf around a closed loop of a magnetic circuit is equal to zero.

A)Kirchhoff’s circuital law
B)Ampere’s circuital law
C)Maxwell’s circuital law
D)Coulomb’s circuital law

48. A substance that attracts pieces iron

A)Magnet
B)All of the answers
C)Conductor
D)Semiconductor

49. The electric field intensity between the parallel plate air capacitor is 20 N/C. If an insulating slab of relative permittivity 5 is placed between the plates, then electric field intensity will be

A)20 N/C
B)40 N/C
C)100 N/C
D)4 N/C

50. What is the unit of magnetomotive force?

A)Ampere- turn
B)Weber
C)Tesla
D)Volt

51. When a conductor is stationary and the magnetic field is moving or changing the emf induced is called

A)Self induced emf
B)Mutually induced emf
C)Dynamically induced emf
D)Statically induced emf

52. The magnetic flux through a wire loop in a magnetic field does not depend on

A)The area of the loop
B)The magnitude of the field
C)The shape of the loop
D)The angle between the plane of the loop and the direction

53. One electron volt (1 eV) is equivalent to _____ joules

A)1.3 x​ 10-19
B)1.4 x​ 10-19
C)1.6 x​ 10-19
D)1.5 x​ 10-19

54. The emf induced in a coil due to the change of its own flux linked with it is called ​

A)Dynamically induced emf
B)Mutually induced emf
C)Self induced emf
D)Statically induced emf

55. Electric field intensity at a point due to a given charge ​_____ if the relative permittivity of the medium decreases.

A)decreases
B)remains unchanged
C)increases
D)becomes zero

56. Hysteresis loss can be reduced by one of the following.

A)Laminating the magnetic circuit
B)Using material narrow hysteresis loop
C)Increasing mmf of the circuit
D)Using ferromagnetic core

57. One that has magnetic poles produced by internal atomic structure with no external current necessary

A)Diamagnetic
B)Permanent magnets
C)Electromagnetic
D)Paramagnetic

58. Core materials of a good relay have ​_____ hysteresis loop.

A)large
B)very narrow
C)narrow
D)very large

59. What is used as the insulating material or dielectric in an electric ion?

A)Mica
B)Titanate compound
C)Oiled paper
D)Paraffin

60. The quantity​ 106 ​maxwells is equivalent to one

A)Weber
B)Gauss
C)Gilbert
D)Tesla

61. One ampere- turn is equivalent to ​_____ gilberts

A)1.26
B)1.16
C)1.46
D)1.36

62. Electromotive force in a circuit

A)maintains circuit resistance
B)is needed to make the circuit complete
C)increases the circuit resistance
D)causes free electrons to flow

63. A negative ion results when an atom gains an additional

A)Proton
B)Neutron
C)Electron
D)Atom

64. When the current flows, the magnetic field ……. conductor is in what direction?

A)Opposite the current direction
B)Omnidirectional
C)The same as the current direction
D)In the direction determined by the left hand rule

65. Calculate the flux density that will be produced by the field intensity of 2000 a. t/m for a permeability of 126 x​ 10-6 ​T/A.t/m

A)0.252 T
B)0.252 x 10-2 ​​G
C)0.252 G
D)0.252 x​​ 10-2 T

66. A magnetic field is

A)The current flow through space around a permanent magnet
B)The force between the plates of a charged capacitor
C)The force set up when current flows through a conductor
D)The force that drives current through a resistor

67. When the relative permeability of a material is much greater than 1, it ​ is called ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ material.

A)non-magnetic
B)paramagnetic
C)diamagnetic
D)ferromagnetic

68. The phenomenon that when an electric current passes through an anisotropic crystal, there is an absorption or liberation of heat due to the non-uniformity in current distribution.

A)Dember effect
B)Bridgman effect
C)Corona effect
D)Destriau effect

69. What is the unit of reluctance?

A)Maxwell
B)Weber
C)Gauss
D)At/Wb

70. A factor used to correct for the electrostatic forces of the more distant ions in an ionic solid.

A)Madelung constant
B)Avogadro’s number
C)Boltzmann’s constant
D)Planck’s constant

71. The air space between poles of magnets

A)Atmosphere
B)Air Gap
C)Vacuum
D)Free space

72. Materials that have very high permeabilities (hundreds and even thousand times of that of free space)

A)Non- magnetic
B)Paramagnetic
C)Diamagnetic
D)Ferromagnetic

73. The phenomenon by which a subtracts pieces of iron

A)Electromagnetism
B)Naturalism
C)Magnetism
D)Materialism

74. Which of the following statements is TRUE?

A)The valence electrons are located in the nucleus of an atom
B)For conductors, the valence electron are strongly attracted to the nucleus
C)The current carriers in conductors are valence electrons
D)Silicon dioxide is a good

75. The reluctance of the magnetic circuit is ​______ relative permeability of the material comprising the circuit.

A)independent of
B)dependent of
C)directly proportional to
D)inversely proportional to

76. A law stating that the magnetic susceptibilities of most paramagnetic substances are inversely proportional to their absolute temperatures.

A)Child’s Law
B)CR Law
C)Curie’s Law
D)Curie-Weiss Law

77. What is the reluctance of a magnetic path having a length of​​ and cross-sectional area of​​ 2 x 10-3 m2?

A)6366 A.t/Wb
B)6000 A.t/Wb
C)​​8 x 10-3 A.t/Wb
D)0.8 A.t/Wb

78. The diameter of a hydrogen atom is approximately _____ cm.

A)1.1 x​​ 10-9
B)1.1 x​​ 10-8
C)1.1 x​​ 10-7
D)1.1 x​​ 10-6

79. The conduction of electricity across the surface of a dielectric is called

A)surface effect
B)creepage
C)skin effect
D)crosstalk

80. What is another name for relative permittivity?

A)Electric intensity
B)Dielectric constant
C)Potential gradient
D)Dielectric strength

81. The emission of electrons from hot bodies is called

A)Skin effect
B)Edison effect
C)Half effect
D)Radiation effect

82. If the solenoid is gripped by the right hand with the fingers pointing the direction of current flow, the outstretched thumb will then point the north pole. This is known as

A)Right hand rule
B)Helix rule
C)Cork screw rule
D)End rule

83. The temperature coefficient of resistance of eureka is

A)negative
B)infinite
C)almost zero
D)positive

84. Used to maintain strength of magnetic field

A)Air gap
B)Container
C)Keeper
D)Source

85. Which of the following is used by permanent magnets as the magnetic material?

A)nickel
B)hardened steel
C)iron
D)soft steel

86. A 6- V battery is connected across a solenoid of 100 turns having a resistance of 2 ohms​​, Calculate the number of ampere-turns?

A)50
B)300
C)600
D)100

87. The force of attraction or repulsion between two magnetic poles is directly proportional to their strengths.

A)Newton’s first law
B)Coulomb’s second law
C)Faraday’s first law of electromagnetic induction
D)Coulomb’s first law

88. A positively charged body has

A)excess of neutrons
B)deficit of electrons
C)deficit of protons
D)excess of electrons

89. A magnetic flux of​​ 2.5 x 104 Wb through an area of 5 x 104​​ square meters results in

A)5000 Tesia of flux density
B)0.5 Tesia of flux density
C)5 Wb
D)​​2.5 x 10-5 Wb of flux

90. The electric flux density is a ______ quantity.

A)scalar
B)variable
C)vector
D)phasor

91. If the value of​​ ​α25 of a conductor is 1/230 per​​ oC, then the value of​​ ​α20 is

A)1/230 per​ oC​
B)1/180 per​ oC​
C)1/280 per​ oC​
D)1/150 per​ oC​

92. Lenz’s law is the consequence of the law of conservation of

A)Momentum
B)Energy
C)Field lines
D)Charge

93. The relation between absolute permittivity of air (​ε0​), absolute permeability of air (µ0) and velocity of light (c) is given by

A)​​µ0 ε0 = C2
B)​​µ0 ε0 = C
C)​​1 / ​​µ0 ε0 = C
D)​​=1 / ​​µ0 ε0 = C2

94. Which of the following electric quantities is vector in character?

A)Charge
B)Energy
C)Potential Difference
D)Field

95. Permeance of a magnetic circuit is _____ the cross-sectional area of the circuit.

A)directly proportional to
B)inversely proportional to
C)dependent of
D)independent of

96. Temporary magnets are commonly employed in

A)magnetos
B)moving coils loudspeakers
C)motors
D)electric instruments

97. The idea of preventing one component from affecting another through their common electric and magnetic field is referred to as

A)Hall effect
B)Limiting
C)Shielding
D)Grounding

98. The force between two magnetic poles is _____ the relative permeability of the medium.

A)independent of
B)equal to
C)directly proportional to
D)inversely proportional to

99. Which of the following is a natural magnet?

A)Soft iron
B)Lodestone
C)Steel
D)Magnesia

100. The B-H curve for ______ is a straight line passing through the origin.

A)air
B)cobalt
C)soft iron
D)hardened steel

101. A law that states that the polarity of the induced voltage will oppose the change in magnetic flux causing the induction.

A)Joule’s law
B)Faraday’s law
C)Lenz’ law
D)Coulomb’s law

102. Which of the following is a vector quantity?

A)Flux density
B)Magnetic permeability
C)Magnetic potential
D)Magnetic field intensity

103. Residual magnetism refers to the flux density, which exists in the iron core when the magnetic field intensity is

A)Unity
B)Maximize
C)Reduced to zero
D)Minimized

104. When the relative permeability of a ​ material ​ is ​ slightly less than 1, ​ it ​ is ​ called ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ material.

A)diamagnetic
B)non-magnetic
C)ferromagnetic
D)paramagnetic

105. The K shell or the first shell has how many permissible number of orbiting electrons?

A)3
B)2
C)4
D)1

106. It is the reciprocal of reluctance and implies the case of readiness with which magnetic flux is developed.

A)Resistance
B)Permeance
C)Inductance
D)Conductance

107. The force acting on a pole of 5 Wb is 25 N. What is the intensity of the magnetic field?

A)5 N/Wb
B)25 N/Wb
C)125 N/Wb
D)0.2 N/Wb

108. The force which set ups or tends to set up magnetic flux in a magnetic circuit

A)Potential ​ difference
B)Electromotive force
C)Magnetomotive force
D)Dynamic force

109. The direction of force o a current carrying conductor placed in a magnetic field can be found by

A)Fleming’s left hand rule
B)using a compass
C)Fleming’s right hand rule
D)Cork screw rule

110. If the resistance of a material 2 m long and​ 2 m2 ​in area of cross-section is 1.6 ×​ 10-8 ohms​, then its resistivity is

A)3.2 ×​ ​10-8 ohm-m
B)0.16 ×​​ ​10-8 ohm-m​
C)0.64 ×​​ ​10-8 ohm-m​
D)1.6 ×​​ ​10-8 ohm-m​

111. One coulomb of charge consists of ​______ electrons.

A)6.24 ×​​ ​1016
B)624 ×​​​ ​1016
C)62.4 ×​​​ ​1016
D)0.624 ×​​​ ​1016

112. The ​ force ​ between two ​ charges placed ​ a given distance apart ​_____ as the relative permittivity of the medium is increased.

A)increases
B)decreases
C)remains unchanged
D)becomes infinite

113. The electrons in the last orbit of an atom are called ______ electrons.

A)free
B)thermionic
C)valence
D)bound

114. The evaporation of electrons from a heated surface is called

A)Convection
B)Conduction
C)Radiation
D)Thermionic emission

115. The unit of flux is ______ in cgs system.

A)Maxwell
B)Oersted
C)Tesia
D)Gilbert

116. If the number of valence electrons of an atom is exactly 4, then the substance is called

A)a conductor
B)a cryogenic conductor
C)a semiconductor
D)an insulator

117. The core of a transformer heats up when its primary is fed from an ac source because of

A)reluctance of core
B)ferromagnetism
C)permeability
D)hysteresis loss

118. The magnetic field of a magnetized iron bar when strongly heated

A)is unchanged
B)Becomes weaker
C)Reverses in direction
D)Becomes stronger

119. What bond is formed when electrons in the outermost energy orbits of the atoms are shared between two or more electrons?

A)Van der Waals
B)Covalent
C)Metallic
D)Ionic

120. The magnetic flux of 2000 lines is how many Maxwells?

A)1000
B)4000
C)8000
D)2000

121. Defined as the ratio of the volume occupied by the atoms or ions in a unit cell divided by the volume of the unit cell and is used to measure the compactness of a crystal.

A)Ionic compacting ratio (ICR)
B)Atomic compacting factor (ACF)
C)Atomic packing factor (APF)
D)Ionic Packing Ratio (IPR)

122. What is the measure of the density and sign of the electric charge at a point relative to that at some time?

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

123. The force between two magnetic poles varies with the distance between them. The variation is _______ to the square of that distance.

A)Inversely proportional
B)Greater than
C)Equal
D)Directly proportional

124. One of the solid structures in which the position of the atoms or ions are predetermined

A)Polycrystalline solid
B)Amorphous solid
C)Crystalline Solid
D)Poly- amorphous solid

125. If the relative permittivity of a material is 10, then its permittivity is

A)4n ×​ 10-7 ​F/m
B)8.854 ×​1011 ​F/m
C)8.854 ×​1012​ F/m
D)4n ×​10-6​ F/m

126. A magnetizing force of 1000 AT/m will produce a flux density of ​ ______​ in air.

A)1.257​ mWbm2​
B)0.63​ mWbm2​
C)0.63​ mWbm2​
D)1.257​ mWbm2​

127. What bond is formed when one or more electrons in the outermost energy orbit of an atom are transferred to another?

A)Ionic
B)Metallic
C)Van der Waals
D)Covalent

128. A length of wire has a resistance of 10 ohms. What is the resistance of a wire of the same material three times as long and twice the cross-sectional area?

A)30 ohms
B)20 ohms
C)15 ohms
D)7 ohms

129. The greater percentage of materials is ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ .

A)paramagnetic
B)non-magnetic
C)ferromagnetic
D)diamagnetic

130. All matters (gas, liquid and solid) are composed of

A)Neutrons
B)Atoms
C)Particles
D)Electrons

131. Which of the following is used by temporary magnets as the magnetic material?

A)Hardened steel
B)Soft iron
C)Cobalt steel
D)Tungsten steel

132. How is mutual inductance between two coils decreased?

A)By using a common core
B)By moving the coils apart
C)By increasing the number of turns of either coil
D)By moving the coils closer

133. What is the maximum number of electrons that can be accommodated in the last orbit of an atom?

A)8
B)2
C)4
D)18

134. Who discovered the relationship between magnetism and electricity that serves as the foundation for the theory of electromagnetism?

A)Hans Christian Oersted
B)Andre Ampere
C)Luigi Galvani
D)Charles Coulomb

135. The mass of a proton is ​______ the mass of an electron.

A)equal to
B)about 1837 times
C)less than
D)200 times

136. The emf induced in a coil due to the changing current of another neighboring coil is called

A)Statically induced emf
B)Self induced emf
C)Mutually induced emf
D)Dynamically induced emf

137. The physical motion resulting from the forces of magnetic fields is called

A)Rotation
B)Torque action
C)Repulsion
D)Motor action

138. The unit of electrical energy is

A)Watt- second
B)Kilowatt-hour
C)Joule
D)All of the answers

139. Magnetic intensity is a

A)Phasor quantity
B)Physical quantity
C)Vector quantity
D)Scalar quantity

140. All magnetic field originates from

A)Magnetic domain
B)moving electric charge
C)Permanent magnets
D)Iron atoms

141. If the magnetic material is located within a coil through which alternating current (60 Hz frequency) flows, then ​_______ hysteresis loops will be formed every second.

A)180
B)30
C)120
D)60

142. An effect which is generally used in the gausameter to measure flux density.

A)Skin effect
B)Hall effect
C)Magnetic effect
D)Flywheel effect

143. Hydrogen is an example of a ______ material.

A)Ferromagnetic
B)Non- magnetic
C)Diamagnetic
D)Paramagnetic

144. The magnitude of the induced emf in a coil is directly proportional to the rate of change of flux linkages. This is known as

A)Faraday’s first law of electromagnetic induction
B)Coulomb’s Law
C)Joule’s Law
D)Faraday’s second law of electromagnetic induction

145. The core of a magnetic equipment uses a magnetic material with

A)Least permeability
B)Low permeability
C)High permeability
D)Moderate permeability

146. The energy stored in an electrostatic field or electromagnetic field is called

A)Kinetic energy
B)Potential energy
C)Electromagnetic energy
D)Rest energy

147. Permanent magnets can be found in

A)earphones
B)dynamic loudspeakers
C)relays
D)electric bells

148. The hot resistance of an incandescent lamp is about ______ its cold resistance.

A)5 times
B)10 times
C)100 times
D)50 times

149. The force between two magnetic poles is _____ their pole strengths.

A)the sum of
B)inversely proportional to
C)the product of
D)directly proportional to ​

150. An atom or a group of atoms that carries a net electric charge.

A)Positive ion
B)Electron
C)Negative ion
D)Ion

151. When the ferromagnetic substance is inserted in a current-carrying solenoid, the magnetic field is

A)Slightly increased
B)Greatly increased
C)Slightly decreased
D)Greatly decreased

152. Electron is a Greek word for

A)amber
B)Heat
C)Fire
D)Stone

153. The temperature coefficient of resistance of semiconductors is

A)infinite
B)zero
C)negative
D)positive

154. Which of the following is a paramagnetic material?

A)Carbon
B)Copper
C)Oxygen
D)Bismuth

155. The magnetic field inside a solenoid

A)decreases with distance from the axis
B)is zero
C)is uniform
D)increases with distance from the axis

156. What is the relative permittivity of air?

A)1
B)8.854 ×​ 10-12
C)0
D)​4π ​×​ 10-7

157. Ohm’s law can be used only to a _____ circuit or component.

A)Trivalent
B)Unilateral
C)Exponential
D)Linear

158. The B-H curve of ​_____ is not a straight line.

A)silicon steel
B)air
C)wood
D)soft iron

159. What is the main advantage of temporary magnets?

A)The magnetic flux can be changed
B)Abundance of ferromagnetic material that can be temporarily magnetized.
C)Hysteresis can be decreased.
D)Magnetic materials can be used.

160. A group of magnetically aligned atoms is called

A)Range
B)Domain
C)Crystal
D)Lattice

161. Electric lines of force leave or enter the charge surface at an angle of

A)​300​
B)​​900​
C)depending upon the angle of launch and entry
D)​​450​

162. Bonding of atoms that is due to the force of attraction between positive ions and a group of negative ions

A)Metallic bond
B)Ionic bond
C)Electrostatic Bond
D)Covalent Bond

163. In electro-mechanical conversion devices like generators and motors the reason why a small air gap is left between the rotor and stator is to

A)decrease the reluctance of magnetic path
B)complete the magnetic path
C)permit mechanical clearance
D)increase flux density in air gap

164. The magnetic materials should have a large hysteresis loss for one of the following applications.

A)Permanent Magnets
B)AC motors
C)Transformers
D)DC generators

165. The induced emf in a wire loop that is moved parallel to a uniform magnetic field is

A)Dependent on the magnitude of the field
B)Dependent on the area of the loop
C)Dependent on the shape of the loop
D)Zero

166. An alloy of 22 percent iron and 78 per cent nickel.

A)Constantan
B)Permalloy
C)Alnico
D)Manganin

167. What is the usual value of leakage coefficient for electrical machines?

A)5 to 10
B)0.5 to 1
C)1 to 5
D)1.15 to 1.25

168. What determines the value of the temperature coefficient of resistance of a material?

A)cross-sectional area
B)length
C)volume
D)nature and temperature

169. If the value of​ α0 ​a conductor is 1/234 per oC, then the value of​ α18 ​is

A)1/272 per​ ​0​C​
B)1/273 per​​ 0​C​​
C)1/218 per​ ​0​C​​
D)1/252 per​ ​0​C​​

170. Which of the following has the least number of valence electrons?

A)Insulator
B)Semiconductor
C)Semi- insulator
D)Conductor

171. Refers to the magnetic lines

A)Magnetomotive force
B)Current
C)Hysteresis
D)Flux

172. The relative permeability of a magnetic material is​ 105. ​What is its permeability?

A)​4π​ ×​ 10-7 ​H/m
B)​4π​ ×​ 10-12 ​H/m
C)​4π​ ×​ 10-2 ​H/m
D)​4π​ ×​ 107 ​H/m

173. The electric potential across part AB of a circuit is 5 V; point A being at higher potential. If a charge of 5 C moves from A to B, then energy released as

A)100 joules
B)25 joules
C)5 joules
D)10 joules

174. The flux density in an air-cored coil is​ 10-3 Wb/m2​.

With a cast iron core of relative permeability 100 inserted, the flux density will become

A)​10-3 Wb/m2
B)​103 Wb/m2
C)​10-2 Wb/m2
D)​10-1 Wb/m2

175. A one cubic cm of copper has how many free electrons at room temperature?

A)80 ×​ 1018​
B)20 × ​1010​
C)50 ×​ 1020​
D)8.5 x​ 1022​

176. The point in a magnet where the intensity of magnetic lines of force is maximum

A)North pole
B)South pole
C)Unit pole
D)Magnetic pole

177. The electric potential at a point in air due to a charge is 21 V. If the air is replaced by a medium of relative permittivity of 3, then electric potential at that point will be

A)21 V
B)42 V
C)7 V
D)63 V

178. A 200-watt lamp working for 24 hours will consume approximately _____ units.

A)50
B)5
C)0.5
D)24

179. The net electrical charge in an isolated system remains constant. This is known as

A)Coulomb’s second law
B)Law of conservation of energy
C)Law of conservation of charge
D)Coulomb’s first law

180. Under ordinary conditions, a body is considered

A)positively charged
B)neutral
C)negatively charged
D)stable

181. Defined as the number of lines per unit area through any substance in a plane at right angles to the lines of force

A)Flux
B)Flux lines
C)Flux density
D)Flux intensity

182. Magnetic effects of the earth as a huge magnet with north and south poles.

A)Terrestrial magnetism
B)Terrestrial ferromagnetism
C)Ferromagnetic
D)Diamagnetic

183. When a wire loop is rotated in a magnetic field the direction of the induced emf changes one in every ​ ____ revolution

A)1/3
B)1/4
C)1/2
D)2/3

184. What is the SI unit of conductance?

A)Ohms
B)Mhos
C)1/Ohms
D)Siemens

185. Hipernik is an alloy containing ______​ iron and ​______ nickel.

A)50% ; 50%
B)70% ; 30%
C)40% ; 60%
D)60% ; 40%

186. A theorem which states that an electric current flowing in a circuit produces a magnetic field at external points equivalent to that due to a magnetic shell whose bounding edge is the conductor and whose strength of the current.

A)Faraday’s law
B)Joule’s law
C)Ampere’s theorem
D)Volta’s theorem

187. Which of the following materials has permeability slightly less than that of free space?

A)Non- magnetic
B)Ferromagnetic
C)Paramagnetic
D)Diamagnetic

188. The total number of magnetic lines of force in a magnetic field is called

A)Magnetic flux density
B)Magnetic flux intensity
C)Magnetic potential
D)Magnetic flux

189. The tiniest element of matter

A)Proton
B)Electron
C)Neutron
D)Atom

190. The ratio of the permeability of the material to the permeability of air or vacuum.

A)Relative permittivity
B)Relative permeability
C)Relative conductivity
D)Relative reluctivity

191. What is the diameter of an atom?

A)About​ 10-10 mm​
B)About​ 10-10 mm​
C)About​ 10-10 ​ ​cm
D)About​ 10-10 ​µm

192. If two similar charges 1 coulomb each are placed 1 m apart in air, then the force of repulsion is

A)9 × ​ 109 ​N
B)5 ×​ 106 ​N
C)8 ×​ 106 ​N
D)​106 ​N​

193. Another term for corona discharge.

A)Corona Effect
B)Lightning
C)Sparking
D)Aurora

194. If the distance between two magnetic poles decreases by 2 times, the force between them

A)increases two times
B)increases four times
C)decreases four times
D)decreases two times

195. A test charge means a charge of

A)+1 C
B)-20 C
C)1 electron
D)-1 C

196. Which element has four valence electrons?

A)Insulator
B)Semi- insulator
C)Semiconductor
D)Conductor

197. Calculate the permeability (in T/A. t/m) of a magnetic material that has a relative permeability of 300

A)3.78 x​ 10-6
B)3.78 x​ 10-5
C)3.78 x​ 10-4
D)3.78 x​ 10-3

198. If a magnetic flux cuts across 200 turns at a rate of 2Wb/s, the induced voltage ​ according to Faraday’s law is about

A)200 V
B)400 V
C)600 V
D)100 V

199. Who discovered superconductivity in 1911?

A)Charles Coulomb
B)Geory Bednorz
C)Alex Muller
D)Kamerlingh Onnes

200. One of the common application of an air- cored choke.

A)Radio frequency
B)Power supply
C)Audio frequency
D)Power transformer

201. The amount of magnetizing force to counter balance the residual magnetism of a magnetic material is referred to as

A)Retentivity
B)Reluctivity
C)Coercivity
D)Susceptivity

202. At/m is a unit of

A)magnetic force
B)reluctance
C)mmf
D)magnetic flux density

203. ​ ​ ______​ is a substance of whose molecules consist of the same kind of atom.

A)Element
B)Compound
C)Isotope
D)Mixture

204. What is used as the dielectric material in high voltage transformers?

A)Mica
B)Oiled paper
C)Paraffin
D)Porcelain

205. A permanent magnet does not exert a force on

A)a stationary electric charge
B)an unmagnetized iron bar
C)a moving electric charge
D)a magnetized iron bar

206. Magnetic fields do not interact with

A)Stationary electric charges
B)Moving permanent magnets
C)Stationary permanent magnets
D)Moving electric charges

207. Which of the following is a paramagnetic material?

A)Copper
B)Oxygen
C)Carbon
D)Bismuth

208. The force between two magnetic poles is _____ their poles strength.

A)equal to
B)directly proportional to
C)directly proportional to the square root of
D)inversely proportional to

209. What is the SI unit of specific resistance or resistivity?

A)Ohm-cm
B)Ohm-circular mil per foot
C)Ohm-m
D)Ohm-circular mil per inch

210. How many electrons are needed in the valence orbit to give a material’s stability?

A)8
B)5
C)6
D)4

211. The permeability of permalloy is

A)Slightly greater than the permeability of air
B)Equal to the permeability of air
C)Slightly less than permeability of air
D)Very much greater than permeability of air

212. The dielectric constant of most materials lies between

A)50 and 100
B)1 and 10
C)20 and 50
D)10 and 20

213. Which of the following magnetic materials can be easily magnetized in both directions?

A)High hysteresis loss materials
B)Low hysteresis loss materials
C)Hard magnetic materials
D)Soft magnetic materials

214. Who discovered the most important electrical effects which is the magnetic effect?

A)Sir Charles Wheatstone
B)Hans Christian Oersted
C)Georg Ohm
D)James Clerk Maxwell

215. Magnetic field intensity is a _________ quantity.

A)phasor
B)scalar
C)variable
D)vector

216. As the magnetic intensity decreases, the relative permeability of a magnetic material

A)remains the same
B)becomes zero
C)decreases
D)increases

217. What is the SI unit of reluctance?

A)N/Wb
B)At/m
C)At
D)At/Wb

218. The straight line passing through the two poles of magnet is called

A)Imaginary axis
B)Real axis
C)Cartesian axis
D)Magnetic axis

219. A magnetic material losses its ferromagnetic properties at a point called

A)Inferred absolute temperature
B)Curie temperature
C)Room temperature
D)Absolute temperature

220. The contribution to the ionization in an ionization chamber by electrons liberated from the walls.

A)Walt effect
B)Hall effect
C)Skin effect
D)Edison effect

221. Lenz’ law states that the direction of the induced emf and hence current

A)Is found by the left hand rule
B)Is determined by the rate of current flux
C)Always opposes the cause producing it
D)Is found by the right hand rule

222. The temperature coefficient of resistance of insulators is

A)negative
B)infinite
C)positive
D)zero

223. If on looking at any one end of a solenoid; the direction of current flow is found to be clockwise then the end under observation is a south pole. This is known as

A)Left hand rule
B)Cork screw rule
C)Right hand rule
D)End Rule

224. _______ is an electromagnet with its core in the form of a close magnetic ring.

A)Cycloid
B)Solenoid
C)Toroid
D)Paraboloid

225. The force of attraction or repulsion between two magnetic poles is inversely proportional to the square of the distance between them.This is known as

A)Coulomb’s first law
B)Newton’s first law
C)Faraday’s first law of electromagnetic induction
D)Coulomb’s second law

226. The permeability of a material having a flux density of​ 5 Wb/m2 ​is​ 10-5 ​H/m. What is the value of magnetizing force?

A)4n ×​ 107 N/Wb​
B)5 ×​ 10-7 N/Wb​​
C)4n ×​​ 10-5 N/Wb​​
D)500 ×​​ 103 N/Wb​​

227. What type of bond is formed when there exists some form of collective interactions between the (negatively charged) electrons and (positively charged) nuclei in a solid?

A)Metallic
B)Van der Waals
C)Ionic
D)Covalent

228. Materials whose permeabilities are slightly greater than that of free space

A)Diamagnetic
B)Ferromagnetic
C)Paramagnetic
D)Non- magnetic

229. Amorphous solid is also called

A)Crystalline
B)Homogenous
C)Polycrystalline
D)Non- crystalline

230. The ​ branch of Engineering ​ which ​ deals ​ with the ​ magnetic ​ effect ​ of electric ​ current is known as

A)Electromagnetism
B)Electrical engineering
C)Magnetism
D)Electronics engineering

231. Permeance is analogous to

A)Resistance
B)Conductance
C)Admittance
D)Reluctance

232. A good conductor has how many valence electrons?

A)8
B)1
C)2
D)4

233. An electron- volt (eV) is a unit of

A)Momentum
B)Energy
C)Potential difference
D)Charge

234. A t/m is a unit of

A)Emf
B)Reluctance
C)Magnetizing force
D)Mmf

235. Hysteresis is a phenomenon of ​ _____ in a magnetic circuit.

A)leading B ahead H
B)lagging of H behind B
C)lagging B behind H
D)setting up constant flux

236. How many turns are needed to produce a magnetomotive force of 1000 A.t for a coil with 6 amperes?

A)67 turns
B)6000 turns
C)167 turns
D)600 turns

237. What revolves about the positive nucleus in a definite orbit?

A)Neutron
B)Atom
C)Electron
D)Proton

238. The property of a material which opposes the creation of magnetic flux in it

A)Resistance
B)Conductance
C)Reluctance
D)Permeance

239. What is the cgs unit of magnetomotive force?

A)Maxwell
B)Ampere- turn
C)Gilbert
D)Weber

240. The ratio of the total flux (flux in iron path) to the useful flux (flux in air gap)

A)Leakage current
B)Leakage flux
C)Leakage coefficient
D)Leakage factor

241. Whenever a flux inking a coil or current changes, an emf is induced in it. This is known as

A)Faraday’s first law of electromagnetic induction
B)Faraday’s second law of electromagnetic induction
C)Joule’s Law
D)Coulomb’s Law

242. What is the SI unit of conductivity?

A)Siemens-m
B)Ohms-m
C)Ohms/m
D)Siemens/m

243. There are how many compounds available in nature?

A)105
B)Unlimited
C)300,000
D)1000

244. What is the value of the absolute permittivity of air?

A)8.854 ×​ 10-12 ​µF/m
B)8.854 ×​ 10-12 ​mF/m
C)8.854 µF/m
D)8.854 ×​ 10-12 ​F/m

245. What determines the atomic number of an element?

A)The number of electrons
B)The number of neutrons and protons
C)The number of neutrons
D)The number of protons

246. The ability of a mechanically stressed ferromagnetic wire to recognize rapid switching of magnetization when subjected to a dc magnetic field.

A)Wiedemann effect
B)Wartheim effect
C)Edison effect
D)Wiegand effect

247. The ​ temperature ​ coefficient ​ of resistance ​ of a conductor ​_____ with an increase in temperature.

A)becomes negative
B)remains the same
C)increases
D)decreases

248. The temperature coefficient of resistance of conductors is

A)negative
B)positive
C)zero
D)infinite

249. How many neutrons does a copper atom have?

A)29
B)32
C)33
D)34

250. A principle that states that only two electrons with different spins are allowed to exist in a given orbit

A)Avogadro’s principle
B)Pauli exclusion principle
C)Bohr’s principle
D)Coulomb’s principle

251. Electrons at the outer shell are called

A)Outer shell electrons
B)Valence electrons
C)Semiconductor electrons
D)Inner shell electrons

252. The process by which an emf and hence current is generated or induced in a conductor when there is a change in the magnetic flux linking the conductor is called

A)Electromagnetic induction
B)Faraday’s law
C)Electromagnetic interference
D)Mutual induction

253. Defined as a closed path in which magnetic induction or flux flows

A)Magnetic circuit
B)Electric circuit
C)Electronic circuit
D)Electromagnetic circuit

254. Steel is hard to magnetize because of its

A)High density
B)High retentivity
C)Low permeability
D)High permeability

255. Mmf in a magnetic circuit corresponds to ______ in an electric circuit

A)Emf
B)Electric Field Intensity
C)Voltage drop
D)Potential gradient

256. A law relating between the magnetic and electric susceptibilities and the absolute temperatures which is followed b ferromagnets, antiferromagnets, non-polar ferroelectrics, antiferroelectrics and some paramagnets.

A)Child’s Law
B)CR Law
C)Curie’s Law
D)Curie-Weiss Law

257. The emf produced in a wire by its motion across a magnetic field does not depend upon the

A)Diameter of the wire
B)Length of the wire
C)Orientation of the wire
D)Flux density of the field

258. Permeability means

A)The magnetization test in the material after exciting field has been removed
B)The strength of an electromagnet
C)The strength of the permanent magnet
D)The conductivity of the material for magnetic lines of force

259. If the number of valence electrons of an atom is less than 4, the substance is called

A)a semiconductor
B)a conductor
C)a superconductor
D)an insulator

260. Paramagnetic substance has a relative permeability of

A)Slightly equal to one
B)Slightly less than one
C)Very much greater than one
D)Equal to one

261. A law that states that the current in a thermionic diode varies directly with the three- halves power of anode voltage and inversely with the square of the distance between the electrodes, provided operating conditions are such that the current is limited only by the space charge.

A)Child’s law
B)Joule’s law
C)Coulomb’s law
D)Hall’s law

262. The customary energy unit in atomic and nuclear physics is

A)Walt- second
B)Joule
C)Volt- coulomb
D)electron-volt

263. The permittivity of a material is given by one of the following formulas.

A)D/E
B)E/D
C)​D2​/E
D)DE

264. What is the other name for dielectric strength?

A)Dielectric constant
B)Breakdown voltage
C)Potential gradient
D)Electric intensity

265. Who developed the electromagnetic theory of light in 1862?

A)James Clerk Maxwell
B)Andre Ampere
C)Heinrich Rudolf Hertz
D)Wilhelm Rontgen

266. Electric field intensity is a ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ .

A)variable
B)scalar
C)vector
D)phasor

267. One farad equals

A)1 newton-meter
B)1 newton/coulomb
C)1 coulomb/volt
D)1 volt/second/ampere

268. What is the SI unit of magnetic flux?

A)Maxwell
B)Gauss
C)Tesla
D)Weber

269. A commercial alloy of aluminum nickel, and iron with cobalt, copper and titanium added to produce about 12 grades.

A)Aluminum
B)Alnico
C)Constantan
D)Brass

270. An alloy of 40 percent iron and 60 percent nickel.

A)Hipernik
B)Alnico
C)Permalloy
D)Manganin

271. The magnetic flux through a coil changes. This results to the induced emf acting in a direction as to

A)Aid the change
B)Neither oppose nor aid the change
C)Oppose the change
D)Either oppose or aid the change

272. Cobalt is an example of a ______ material.

A)Diamagnetic
B)Paramagnetic
C)Non-magnetic
D)Ferromagnetic

273. Whenever a conductor cuts magnetic flux, an emf is induced in it. This is known as

A)Ohm’s law
B)Joule’s law
C)Coulomb’s law
D)Faraday’s law

274. If the length and area of cross-section of a wire are doubled, then its resistance

A)becomes four times
B)remains the same
C)becomes two times
D)becomes sixteen times

275. Flux density is measured in

A)Ampere- turn
B)Tesia
C)Weber
D)Maxwell

276. The magnetic potential in a magnetic circuit can be measured in terms of

A)Farad
B)Mmf
C)Emf
D)Coulomb

277. The phenomenon by which a magnetic substance becomes a magnet when it is place near a magnet

A)Magnetic phenomenon
B)Magnetic induction
C)Electromagnetic induction
D)Magnetic effect

278. States that the ratio of the thermal conductivity is proportional to the absolute temperature for all metals.

A)Wien’s displacement law
B)Hartleys law
C)Wiedemann Franz law
D)Hall’s law

279. Small voltages generated by a conductor with current in an external magnetic field.

A)Flywheel Effect
B)Hall effect
C)Magnetic effect
D)Skin effect

280. A negatively charge body has

A)excess of protons
B)excess of electrons
C)deficit of electrons
D)deficit of neutrons

281. Defined as the flux density produced in it due to its own induced magnetism

A)Electric field intensity
B)Electromagnetic field intensity
C)Magnetic field intensity
D)Intensity magnetization

282. Germanium atom has ​ _____​ protons and _____​ electrons.

A)34, 34
B)32, 32
C)42, 32
D)32, 42

283. A magnetic pole produces 5000 field lines. How much is the flux in webers?

A)50 ×​ 10-6​
B)500 ×​ 10-5​
C)5 ×​ 10-6​
D)500 ×​ 10-6​

284. Electric field intensity at a point is numerically equal to ​_____ at that point.

A)the force
B)potential difference
C)potential gradient
D)dielectric constant

285. A germanium atom has an atomic weight of 72. How many neutrons are there?

A)40
B)34
C)36
D)32

286. If the number of valence electrons of an atom is more than 4, the substance is called

A)a semi-insulator
B)an insulator
C)a semiconductor
D)a conductor

287. The resistance of a material is _______ its area of cross-section.

A)equal to
B)independent of
C)inversely proportional to
D)directly proportional

288. The unit of flux density is

A)At/m
B)Tesla
C)Wb/m
D)N/Wb

289. The reluctance of a magnetic circuit is not dependent on which of the following?

A)Flux density in the circuit
B)Current in the coil
C)Number of turns of coil
D)Magnetomotive force

290. The quantity of magnetism retained by a magnetic material after withdrawal of the magnetizing force is called

A)Leftover magnetism
B)Coercivity
C)Residual magnetism
D)Hysteresis

291. One oersted (Oe) is equivalent to ​______ Gb/cm.

A)100
B)10
C)1
D)1000

292. The property of magnetic materials of retaining magnetism after withdrawal of the magnetizing force is known as

A)Conductivity
B)Resistivity
C)Reluctivity
D)Retentivity

293. The force acting on a unit n- pole placed at that point is called

A)Electromagnetic field intensity
B)Intensity magnetization
C)Magnetic field intensity
D)Electric field intensity

294. If you hold the conductor with right hand so that the stretched thumb points in the direction of the current, then encircling fingers will give the direction of magnetic lines of force round the conductor. This is known as

A)Left hand cork screw rule
B)Left hand rule
C)Right hand cork screw rule
D)Right hand rule

295. Gases whose particles are charged are known as

A)Insulators
B)Plasma
C)Conductors
D)Gaseous Conductors

296. Which of the following is a diamagnetic material?

A)Cobalt
B)Aluminum
C)Air
D)Silver

297. The magnetic energy stored in an inductor is ______​ current.

A)Inversely proportional to
B)Directly proportional to
C)Directly proportional to the square of
D)Inversely proportional to the square of

298. The magnetic field of a bar magnet most closely resembles the magnetic field of

A)a horseshoe magnet
B)a straight current- carrying wire
C)a current- carrying wire loop
D)a stream of electrons moving parallel to one another

299. The potential at a point due to a charge is 15 V. If the distance is increased three times, the potential at the point will be

A)15 V
B)5 V
C)18 V
D)45 V

300. The current of electric circuit is analogous to which quantity of a magnetic circuit

A)Flux density
B)Flux
C)Mmf
D)Reluctivity

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