1. The study of electric current and magnetic fields together is called
A) Electromagnetism
B) Magnetism
C) Electrostatics
D) Electrochemistry
Answer: A) Electromagnetism
Explanation: Electromagnetism deals with the interaction between electricity and magnetism.
2. The scientist who discovered the magnetic effect of electric current is
A) Oersted
B) Faraday
C) Maxwell
D) Ampere
Answer: A) Oersted
Explanation: Oersted discovered that current in a wire produces a magnetic field around it.
3. The magnetic field around a current-carrying wire is in the form of
A) Concentric circles
B) Straight lines
C) Random curves
D) Elliptical rings
Answer: A) Concentric circles
Explanation: Oersted showed that the magnetic field lines form concentric circles around the wire.
4. The direction of the magnetic field around a current-carrying wire can be found by
A) Right-hand thumb rule
B) Left-hand rule
C) Fleming’s rule
D) Ampere’s rule
Answer: A) Right-hand thumb rule
Explanation: When the thumb points in current’s direction, fingers curl in the magnetic field direction.
5. A solenoid is
A) A coil of insulated wire
B) A straight conductor
C) A permanent magnet
D) A battery
Answer: A) A coil of insulated wire
Explanation: When current passes through it, the solenoid produces a magnetic field similar to a bar magnet.
6. The magnetic field inside a solenoid is
A) Uniform
B) Non-uniform
C) Zero
D) Irregular
Answer: A) Uniform
Explanation: The field inside is uniform and parallel to the axis of the solenoid.
7. The magnetic field around a solenoid resembles that of a
A) Bar magnet
B) Circular loop
C) Straight wire
D) Coil
Answer: A) Bar magnet
Explanation: One end behaves like a north pole and the other like a south pole.
8. The polarity of an electromagnet can be changed by
A) Reversing the direction of current
B) Increasing the wire length
C) Changing the coil material
D) Heating the coil
Answer: A) Reversing the direction of current
9. The strength of an electromagnet increases when
A) Current or coil turns increase
B) Wire is shortened
C) Core is removed
D) Current is stopped
Answer: A) Current or coil turns increase
Explanation: Stronger current and more turns produce stronger magnetic fields.
10. The material used as a core in an electromagnet is
A) Soft iron
B) Steel
C) Copper
D) Aluminium
Answer: A) Soft iron
Explanation: Soft iron magnetizes easily and loses magnetism quickly when current stops.
11. An electromagnet works on the principle of
A) Magnetic effect of electric current
B) Electrostatic induction
C) Heating effect
D) Light emission
Answer: A) Magnetic effect of electric current
12. The device that converts electrical energy into mechanical energy using magnetic effect is
A) Electric motor
B) Generator
C) Transformer
D) Battery
Answer: A) Electric motor
13. The device that converts mechanical energy into electrical energy using magnetic induction is
A) Electric generator
B) Transformer
C) Motor
D) Battery
Answer: A) Electric generator
14. The principle of an electric motor is based on
A) Force on a current-carrying conductor in a magnetic field
B) Heating effect
C) Resistance
D) Reflection
Answer: A) Force on a current-carrying conductor in a magnetic field
15. The direction of motion of the conductor in a magnetic field is given by
A) Fleming’s left-hand rule
B) Right-hand rule
C) Thumb rule
D) Ampere’s rule
Answer: A) Fleming’s left-hand rule
Explanation: It gives the direction of force, magnetic field, and current.
16. The principle of an electric generator is
A) Electromagnetic induction
B) Electrostatic effect
C) Chemical effect
D) Magnetic effect
Answer: A) Electromagnetic induction
17. The phenomenon of producing current by changing magnetic field is called
A) Electromagnetic induction
B) Electrolysis
C) Magnetization
D) Conduction
Answer: A) Electromagnetic induction
18. Electromagnetic induction was discovered by
A) Michael Faraday
B) Oersted
C) Ampere
D) Tesla
Answer: A) Michael Faraday
19. The device that increases or decreases AC voltage is
A) Transformer
B) Generator
C) Motor
D) Battery
Answer: A) Transformer
Explanation: A transformer transfers energy between circuits through electromagnetic induction.
20. A transformer works only on
A) Alternating current (AC)
B) Direct current (DC)
C) Both
D) Static electricity
Answer: A) Alternating current (AC)
Explanation: Because AC continuously changes direction, inducing voltage in another coil.
21. The soft iron core in a transformer is used to
A) Increase magnetic flux
B) Decrease weight
C) Prevent short circuit
D) Produce sound
Answer: A) Increase magnetic flux
22. The energy loss in a transformer due to repeated magnetization is called
A) Hysteresis loss
B) Heat loss
C) Radiation loss
D) Leakage loss
Answer: A) Hysteresis loss
23. The device used to detect the presence of current is
A) Galvanometer
B) Ammeter
C) Voltmeter
D) Wattmeter
Answer: A) Galvanometer
24. The instrument used to measure electric current is
A) Ammeter
B) Voltmeter
C) Wattmeter
D) Galvanometer
Answer: A) Ammeter
25. The instrument used to measure voltage is
A) Voltmeter
B) Ammeter
C) Galvanometer
D) Ohmmeter
Answer: A) Voltmeter
26. The part of a motor that rotates is called
A) Armature
B) Stator
C) Core
D) Brush
Answer: A) Armature
27. The stationary part of an electric motor is called
A) Stator
B) Rotor
C) Commutator
D) Coil
Answer: A) Stator
28. The device used to convert DC into AC is
A) Inverter
B) Transformer
C) Rectifier
D) Motor
Answer: A) Inverter
29. The device used to convert AC into DC is
A) Rectifier
B) Inverter
C) Transformer
D) Motor
Answer: A) Rectifier
30. The rule used to find direction of induced current is
A) Fleming’s right-hand rule
B) Left-hand rule
C) Thumb rule
D) Maxwell’s rule
Answer: A) Fleming’s right-hand rule
31. The magnetic field lines outside a bar magnet run from
A) North to South
B) South to North
C) Random
D) None
Answer: A) North to South
32. The magnetic field inside a bar magnet runs from
A) South to North
B) North to South
C) Circular
D) Random
Answer: A) South to North
33. The energy conversion in an electric motor is
A) Electrical to mechanical
B) Mechanical to electrical
C) Heat to light
D) Light to electrical
Answer: A) Electrical to mechanical
34. The energy conversion in a generator is
A) Mechanical to electrical
B) Electrical to mechanical
C) Chemical to electrical
D) Heat to mechanical
Answer: A) Mechanical to electrical
35. A transformer works on the principle of
A) Mutual induction
B) Static induction
C) Conduction
D) Magnetization
Answer: A) Mutual induction
36. The scientist who formulated laws of electromagnetic induction is
A) Faraday
B) Ampere
C) Tesla
D) Newton
Answer: A) Faraday
37. The magnetic field around a straight current-carrying conductor was explained by
A) Oersted
B) Faraday
C) Newton
D) Ampere
Answer: A) Oersted
38. The strength of a magnetic field depends on
A) Current and distance from conductor
B) Shape of wire
C) Color of wire
D) Pressure
Answer: A) Current and distance from conductor
39. The instrument used to observe changing magnetic fields is
A) Magnetic compass
B) Ammeter
C) Voltmeter
D) Barometer
Answer: A) Magnetic compass
40. The core of an electromagnet must have
A) High permeability
B) High resistance
C) Low weight
D) Large size
Answer: A) High permeability
41. Electromagnetic waves are produced by
A) Accelerating electric charges
B) Stationary charges
C) Magnetic poles
D) Electric current alone
Answer: A) Accelerating electric charges
42. The scientist who unified electricity and magnetism mathematically was
A) James Clerk Maxwell
B) Faraday
C) Oersted
D) Ampere
Answer: A) James Clerk Maxwell
43. The part of an electric motor that reverses current direction is
A) Commutator
B) Coil
C) Rotor
D) Core
Answer: A) Commutator
44. A moving coil galvanometer can be converted into an ammeter by
A) Connecting a low resistance in parallel
B) High resistance in series
C) Removing coil
D) Reversing polarity
Answer: A) Connecting a low resistance in parallel
45. A moving coil galvanometer can be converted into a voltmeter by
A) Connecting a high resistance in series
B) Low resistance in parallel
C) Changing coil
D) Reversing current
Answer: A) Connecting a high resistance in series
46. The direction of induced current always opposes the cause producing it — this is
A) Lenz’s Law
B) Ohm’s Law
C) Coulomb’s Law
D) Faraday’s Law
Answer: A) Lenz’s Law
47. The electromagnetic device that converts sound into electrical signals is
A) Microphone
B) Loudspeaker
C) Motor
D) Generator
Answer: A) Microphone
48. The device that converts electrical signals into sound is
A) Loudspeaker
B) Microphone
C) Generator
D) Motor
Answer: A) Loudspeaker
49. A current-carrying coil placed in a magnetic field experiences
A) A turning force
B) No force
C) Repulsion
D) Compression
Answer: A) A turning force
50. The unit of magnetic field strength is
A) Tesla
B) Volt
C) Watt
D) Ampere
Answer: A) Tesla
51. The phenomenon of producing induced current in a coil by changing the magnetic field is known as
A) Electromagnetic induction
B) Magnetic effect
C) Electrostatics
D) Ionization
Answer: A) Electromagnetic induction
Explanation: A current is induced in a coil when the magnetic field around it changes.
52. The scientist who demonstrated electromagnetic induction is
A) Michael Faraday
B) Ampere
C) Oersted
D) Newton
Answer: A) Michael Faraday
53. The direction of induced current is given by
A) Fleming’s right-hand rule
B) Fleming’s left-hand rule
C) Ampere’s law
D) Lenz’s law
Answer: A) Fleming’s right-hand rule
54. The rule used to find the direction of motion of a current-carrying conductor in a magnetic field is
A) Fleming’s left-hand rule
B) Fleming’s right-hand rule
C) Thumb rule
D) Faraday’s law
Answer: A) Fleming’s left-hand rule
55. The magnetic field is strongest
A) Near the poles of a magnet
B) At the center
C) Far from magnet
D) Between midpoints
Answer: A) Near the poles of a magnet
56. The direction of magnetic field lines around a straight wire carrying current is
A) Circular
B) Straight
C) Parallel
D) Random
Answer: A) Circular
57. The magnetic field inside a current-carrying solenoid is
A) Uniform and parallel
B) Circular
C) Weak
D) Irregular
Answer: A) Uniform and parallel
58. The device that produces a strong magnetic field is
A) Electromagnet
B) Permanent magnet
C) Battery
D) Generator
Answer: A) Electromagnet
59. The strength of an electromagnet can be increased by
A) Increasing current or turns
B) Decreasing current
C) Using wooden core
D) Using copper core
Answer: A) Increasing current or turns
60. The energy conversion in an electric generator is
A) Mechanical to electrical
B) Electrical to mechanical
C) Chemical to electrical
D) Electrical to heat
Answer: A) Mechanical to electrical
61. The energy conversion in an electric motor is
A) Electrical to mechanical
B) Mechanical to electrical
C) Electrical to light
D) Thermal to electrical
Answer: A) Electrical to mechanical
62. The working principle of a transformer is
A) Mutual induction
B) Electromagnetic force
C) Static induction
D) Heat conduction
Answer: A) Mutual induction
63. A step-up transformer
A) Increases voltage
B) Decreases voltage
C) Keeps voltage constant
D) Increases current
Answer: A) Increases voltage
64. A step-down transformer
A) Decreases voltage
B) Increases voltage
C) Increases frequency
D) Converts DC to AC
Answer: A) Decreases voltage
65. The core of a transformer is made of
A) Soft iron
B) Steel
C) Copper
D) Aluminium
Answer: A) Soft iron
Explanation: Soft iron allows efficient magnetic flux linkage between coils.
66. The direction of the magnetic field around a current-carrying conductor depends on
A) Direction of current
B) Material of wire
C) Temperature
D) Resistance
Answer: A) Direction of current
67. The force on a current-carrying conductor in a magnetic field is
A) Perpendicular to both current and field
B) Along the current
C) Along the field
D) Zero
Answer: A) Perpendicular to both current and field
68. Electromagnetic induction produces
A) Induced current and emf
B) Electric charge
C) Static energy
D) Resistance
Answer: A) Induced current and emf
69. The device that converts AC voltage levels is
A) Transformer
B) Motor
C) Generator
D) Battery
Answer: A) Transformer
70. The phenomenon of self-induction occurs in
A) A single coil
B) Two coils
C) Magnetic material
D) Solids
Answer: A) A single coil
Explanation: When current in a coil changes, it induces emf in the same coil.
71. The phenomenon of mutual induction occurs in
A) Two nearby coils
B) Single coil
C) Permanent magnet
D) Static charge
Answer: A) Two nearby coils
72. The property of a coil that opposes change in current is called
A) Inductance
B) Capacitance
C) Resistance
D) Conductance
Answer: A) Inductance
73. The instrument used to measure the strength of magnetic field is
A) Magnetometer
B) Barometer
C) Thermometer
D) Voltmeter
Answer: A) Magnetometer
74. Electromagnetic waves travel at the speed of
A) Light
B) Sound
C) Water waves
D) Air currents
Answer: A) Light
Explanation: Electromagnetic waves travel at the same speed as light in vacuum.
75. Electromagnetic waves require
A) No medium for propagation
B) Air medium
C) Solid medium
D) Liquid medium
Answer: A) No medium for propagation
76. The electromagnetic spectrum includes
A) Radio, microwaves, infrared, visible, UV, X-rays, gamma rays
B) Only light
C) Only X-rays
D) Only UV
Answer: A) Radio, microwaves, infrared, visible, UV, X-rays, gamma rays
77. The electromagnetic wave with highest frequency is
A) Gamma rays
B) X-rays
C) Ultraviolet rays
D) Radio waves
Answer: A) Gamma rays
78. The electromagnetic wave with longest wavelength is
A) Radio waves
B) X-rays
C) UV rays
D) Gamma rays
Answer: A) Radio waves
79. The electromagnetic wave used in TV and radio broadcasting is
A) Radio wave
B) Gamma ray
C) X-ray
D) Ultraviolet
Answer: A) Radio wave
80. The electromagnetic wave used in microwave ovens is
A) Microwaves
B) Infrared
C) Ultraviolet
D) Gamma rays
Answer: A) Microwaves
81. The electromagnetic wave responsible for heat is
A) Infrared rays
B) Ultraviolet rays
C) X-rays
D) Gamma rays
Answer: A) Infrared rays
82. The electromagnetic waves responsible for causing sunburn are
A) Ultraviolet rays
B) Infrared rays
C) Radio waves
D) Microwaves
Answer: A) Ultraviolet rays
83. The electromagnetic waves used for medical imaging are
A) X-rays
B) Infrared rays
C) Ultraviolet rays
D) Radio waves
Answer: A) X-rays
84. The electromagnetic waves emitted by radioactive decay are
A) Gamma rays
B) X-rays
C) Microwaves
D) Infrared rays
Answer: A) Gamma rays
85. The electromagnetic wave used in radar systems is
A) Microwaves
B) Infrared rays
C) X-rays
D) Gamma rays
Answer: A) Microwaves
86. The scientist who discovered electromagnetic waves was
A) Heinrich Hertz
B) Faraday
C) Ampere
D) Oersted
Answer: A) Heinrich Hertz
87. The SI unit of magnetic flux is
A) Weber
B) Tesla
C) Volt
D) Watt
Answer: A) Weber
88. The SI unit of magnetic field strength is
A) Tesla
B) Newton
C) Ampere
D) Joule
Answer: A) Tesla
89. The magnetic field intensity is directly proportional to
A) Current
B) Voltage
C) Resistance
D) Pressure
Answer: A) Current
90. The force experienced by a moving charge in a magnetic field depends on
A) Velocity and field strength
B) Mass only
C) Temperature
D) Volume
Answer: A) Velocity and field strength
91. The instrument used to visualize waveforms of electrical signals is
A) Cathode Ray Oscilloscope (CRO)
B) Voltmeter
C) Ammeter
D) Magnetometer
Answer: A) Cathode Ray Oscilloscope (CRO)
92. The magnetic lines of force never
A) Intersect each other
B) Form closed loops
C) Have direction
D) Exist in space
Answer: A) Intersect each other
Explanation: At a point, the magnetic field has only one direction, so lines never cross.
93. The strength of Earth’s magnetic field is maximum at
A) Poles
B) Equator
C) Center
D) Tropics
Answer: A) Poles
94. The magnetic field of Earth is caused by
A) Motion of molten iron in Earth’s core
B) Rotation of Earth
C) Sunlight
D) Gravitational pull
Answer: A) Motion of molten iron in Earth’s core
95. The principle of electric bell is based on
A) Magnetic effect of current
B) Heating effect
C) Chemical effect
D) Electrolysis
Answer: A) Magnetic effect of current
96. The device that stores magnetic energy is
A) Inductor
B) Capacitor
C) Resistor
D) Transformer
Answer: A) Inductor
97. The discovery that light is an electromagnetic wave was made by
A) James Clerk Maxwell
B) Hertz
C) Newton
D) Faraday
Answer: A) James Clerk Maxwell
98. The electromagnetic wave used for communication with satellites is
A) Microwaves
B) X-rays
C) Gamma rays
D) Infrared rays
Answer: A) Microwaves
99. The magnetic force is strongest when the conductor and magnetic field are
A) Perpendicular to each other
B) Parallel
C) Opposite
D) In same line
Answer: A) Perpendicular to each other
100. Electromagnetism is the basis of
A) Motors, generators, transformers, and communication systems
B) Sound and heat
C) Friction
D) Gravity
Answer: A) Motors, generators, transformers, and communication systems
Explanation: Almost all modern electrical machines and technologies rely on electromagnetic principles.