Electromagnetism MCQs

What is Electromagnetism?

Electromagnetism is a fundamental chapter in Physics that explores the interaction between electric and magnetic fields and the principles underlying electromagnetic forces. This chapter introduces students to the concept of electromagnetism, including how electric currents generate magnetic fields and how changing magnetic fields induce electric currents. The unit covers key topics such as Ampère’s Law, Faraday’s Law of Induction, and Maxwell’s Equations, which form the basis of classical electromagnetism. Students also learn about practical applications, including electromagnetic waves and their use in communication technologies.

Key Topics in Electromagnetism:

• Magnetic Fields: Understanding the nature and sources of magnetic fields, including magnetic forces on moving charges and current-carrying conductors.
• Ampère’s Law: Exploring the relationship between electric currents and the magnetic fields they produce.
• Faraday’s Law of Induction: Analyzing how changing magnetic fields induce electromotive force (EMF) and electric currents in conductors.
• Electromagnetic Waves: Studying the propagation of electromagnetic waves and their properties, such as wavelength, frequency, and speed.
• Maxwell’s Equations: Learning the set of four fundamental equations that describe how electric and magnetic fields interact and propagate.
• Applications of Electromagnetism: Exploring real-world applications, including electric motors, transformers, generators, and wireless communication technologies.

Benefits of Studying Electromagnetism:

• Foundational Knowledge: Provides a deep understanding of the interaction between electric and magnetic fields, essential for studying advanced topics in Physics and engineering.
• Technological Insights: Equips students with knowledge applicable to a wide range of technologies, including electronics, telecommunications, and power generation.
• Career Preparation: Prepares students for careers in electrical engineering, physics research, and other fields that rely on electromagnetic principles.

This chapter is crucial for students to develop a comprehensive understanding of electromagnetism, which is fundamental to many modern technologies and scientific advancements. Whether preparing for exams or pursuing a career in science and engineering, mastering Electromagnetism is key to achieving success.

1. The force experienced by a current-carrying conductor in a magnetic field is called:
   • a) Electrostatic force
   • b) Magnetic force
   • c) Gravitational force
   • d) Frictional force
     Answer: b) Magnetic force
2. The unit of magnetic flux is:
   • a) Tesla
   • b) Weber
   • c) Ampere
   • d) Volt
     Answer: b) Weber
3. The direction of the magnetic field around a current-carrying wire is given by:
   • a) Coulomb’s Law
   • b) Ohm’s Law
   • c) Faraday’s Law
   • d) Right-Hand Rule
     Answer: d) Right-Hand Rule
4. The magnetic field at the center of a circular loop of radius rrr carrying a current III is:
   • a) μ0I2πr\frac{\mu_0 I}{2\pi r}2πrμ0​I​
   • b) μ0I4πr\frac{\mu_0 I}{4\pi r}4πrμ0​I​
   • c) μ0I2r\frac{\mu_0 I}{2r}2rμ0​I​
   • d) μ0I4r\frac{\mu_0 I}{4r}4rμ0​I​
     Answer: a) μ0I2r\frac{\mu_0 I}{2r}2rμ0​I​
5. The force between two parallel currents-carrying conductors is:
   • a) Directly proportional to the product of the currents
   • b) Inversely proportional to the distance between them
   • c) Independent of the distance between them
   • d) Both a and b
     Answer: d) Both a and b
6. The SI unit of magnetic field strength is:
   • a) Tesla
   • b) Weber
   • c) Henry
   • d) Ampere
     Answer: a) Tesla
7. A magnetic field is created by:
   • a) A stationary electric charge
   • b) A moving electric charge
   • c) A permanent magnet only
   • d) A stationary magnet
     Answer: b) A moving electric charge
8. The magnetic field lines around a bar magnet are:
   • a) Straight and parallel
   • b) Circular around the north pole
   • c) Circular around the south pole
   • d) Closed loops running from the north to the south pole
     Answer: d) Closed loops running from the north to the south pole
9. The phenomenon of electromagnetic induction was discovered by:
   • a) Michael Faraday
   • b) James Clerk Maxwell
   • c) André-Marie Ampère
   • d) Heinrich Hertz
     Answer: a) Michael Faraday
10. The induced EMF in a coil is proportional to:
    • a) The rate of change of current
    • b) The rate of change of magnetic flux
    • c) The rate of change of temperature
    • d) The rate of change of resistance
      Answer: b) The rate of change of magnetic flux
11. Lenz’s Law states that the direction of the induced current is such that:
    • a) It opposes the change in magnetic flux
    • b) It enhances the change in magnetic flux
    • c) It has no effect on the change in magnetic flux
    • d) It is equal to the change in magnetic flux
      Answer: a) It opposes the change in magnetic flux
12. The unit of magnetic flux is:
    • a) Weber
    • b) Tesla
    • c) Henry
    • d) Ampere
      Answer: a) Weber
13. A solenoid is:
    • a) A coil of wire wound into a cylindrical shape
    • b) A type of magnet
    • c) A type of electric current
    • d) A type of capacitor
      Answer: a) A coil of wire wound into a cylindrical shape
14. The magnetic field inside a solenoid is:
    • a) Zero
    • b) Uniform and parallel to the axis
    • c) Circular and perpendicular to the axis
    • d) Non-uniform and radial
      Answer: b) Uniform and parallel to the axis
15. The magnetic force on a charged particle moving in a magnetic field is maximized when:
    • a) The particle is stationary
    • b) The particle is moving parallel to the field
    • c) The particle is moving perpendicular to the field
    • d) The field is zero
      Answer: c) The particle is moving perpendicular to the field
16. The direction of the force on a current-carrying conductor in a magnetic field can be determined using:
    • a) Fleming’s Left-Hand Rule
    • b) Fleming’s Right-Hand Rule
    • c) Lenz’s Law
    • d) Faraday’s Law
      Answer: a) Fleming’s Left-Hand Rule
17. The magnetic field at a distance rrr from a long straight conductor carrying a current III is:
    • a) μ0I2πr\frac{\mu_0 I}{2\pi r}2πrμ0​I​
    • b) μ0I4πr\frac{\mu_0 I}{4\pi r}4πrμ0​I​
    • c) μ0Ir\frac{\mu_0 I}{r}rμ0​I​
    • d) μ0Ir2\frac{\mu_0 I}{r^2}r2μ0​I​
      Answer: a) μ0I2πr\frac{\mu_0 I}{2\pi r}2πrμ0​I​
18. The magnetic flux through a surface is given by:
    • a) B×A×cos⁡θB \times A \times \cos \thetaB×A×cosθ
    • b) B×A×sin⁡θB \times A \times \sin \thetaB×A×sinθ
    • c) B×A×tan⁡θB \times A \times \tan \thetaB×A×tanθ
    • d) B×A×cot⁡θB \times A \times \cot \thetaB×A×cotθ
      Answer: a) B×A×cos⁡θB \times A \times \cos \thetaB×A×cosθ
19. A moving coil galvanometer can be converted into a voltmeter by:
    • a) Connecting a low resistance in series
    • b) Connecting a high resistance in series
    • c) Connecting a high resistance in parallel
    • d) Connecting a low resistance in parallel
      Answer: b) Connecting a high resistance in series
20. The force on a charged particle moving in a magnetic field is:
    • a) F=qvBsin⁡θF = qvB \sin \thetaF=qvBsinθ
    • b) F=qvBcos⁡θF = qvB \cos \thetaF=qvBcosθ
    • c) F=qvBF = qvBF=qvB
    • d) F=qvBsin⁡θF = \frac{qvB}{\sin \theta}F=sinθqvB​
      Answer: a) F=qvBsin⁡θF = qvB \sin \thetaF=qvBsinθ
21. The magnetic field produced by a current-carrying solenoid is:
    • a) Zero
    • b) Uniform inside and outside the solenoid
    • c) Uniform inside and non-uniform outside
    • d) Non-uniform inside and uniform outside
      Answer: c) Uniform inside and non-uniform outside
22. The magnetic field at the center of a circular loop of radius rrr carrying a current III is:
    • a) μ0I2r\frac{\mu_0 I}{2r}2rμ0​I​
    • b) μ0I4r\frac{\mu_0 I}{4r}4rμ0​I​
    • c) μ0Iπr\frac{\mu_0 I}{\pi r}πrμ0​I​
    • d) μ0I2πr\frac{\mu_0 I}{2\pi r}2πrμ0​I​
      Answer: d) μ0I2πr\frac{\mu_0 I}{2\pi r}2πrμ0​I​
23. The force between two parallel wires carrying currents I1I_1I1​ and I2I_2I2​ separated by a distance ddd is given by:
    • a) μ0I1I22πd\frac{\mu_0 I_1 I_2}{2\pi d}2πdμ0​I1​I2​​
    • b) μ0I1I2d\frac{\mu_0 I_1 I_2}{d}dμ0​I1​I2​​
    • c) μ0I1I24πd\frac{\mu_0 I_1 I_2}{4\pi d}4πdμ0​I1​I2​​
    • d) μ0I1I2d2π\frac{\mu_0 I_1 I_2 d}{2\pi}2πμ0​I1​I2​d​
      Answer: a) μ0I1I22πd\frac{\mu_0 I_1 I_2}{2\pi d}2πdμ0​I1​I2​​
24. The unit of magnetic field strength is:
    • a) Tesla
    • b) Weber
    • c) Coulomb
    • d) Ampere
      Answer: a) Tesla
25. The formula for the magnetic field at the center of a solenoid is:
    • a) B=μ0nIB = \mu_0 n IB=μ0​nI
    • b) B=μ0InB = \frac{\mu_0 I}{n}B=nμ0​I​
    • c) B=μ0nIB = \frac{\mu_0 n}{I}B=Iμ0​n​
    • d) B=μ0nI2B = \frac{\mu_0 n I}{2}B=2μ0​nI​
      Answer: a) B=μ0nIB = \mu_0 n IB=μ0​nI
26. The magnetic flux through a surface is given by:
    • a) B×A×sin⁡θB \times A \times \sin \thetaB×A×sinθ
    • b) B×A×cos⁡θB \times A \times \cos \thetaB×A×cosθ
    • c) B×AB \times AB×A
    • d) B×Acos⁡θ\frac{B \times A}{\cos \theta}cosθB×A​
      Answer: b) B×A×cos⁡θB \times A \times \cos \thetaB×A×cosθ
27. In a moving coil galvanometer, the deflection is:
    • a) Directly proportional to the current
    • b) Inversely proportional to the current
    • c) Directly proportional to the voltage
    • d) Inversely proportional to the voltage
      Answer: a) Directly proportional to the current
28. The principle of operation of a transformer is based on:
    • a) Faraday’s Law of Electromagnetic Induction
    • b) Ampère’s Law
    • c) Gauss’s Law
    • d) Coulomb’s Law
      Answer: a) Faraday’s Law of Electromagnetic Induction
29. The magnetic field at a point due to a long straight wire carrying current decreases:
    • a) With the square of the distance from the wire
    • b) With the distance from the wire
    • c) With the cube of the distance from the wire
    • d) Inversely with the square of the distance from the wire
      Answer: b) With the distance from the wire
30. The direction of induced EMF in a coil is given by:
    • a) Lenz’s Law
    • b) Fleming’s Left-Hand Rule
    • c) Right-Hand Rule
    • d) Faraday’s Law
      Answer: a) Lenz’s Law
31. The force between two parallel current-carrying conductors is:
    • a) Directly proportional to the product of the currents
    • b) Inversely proportional to the product of the currents
    • c) Directly proportional to the distance between them
    • d) Inversely proportional to the distance between them
      Answer: d) Inversely proportional to the distance between them
32. The SI unit of electric current is:
    • a) Ampere
    • b) Volt
    • c) Ohm
    • d) Tesla
      Answer: a) Ampere
33. The magnetic field lines of a bar magnet are:
    • a) Always closed loops
    • b) Always straight lines
    • c) Radial lines
    • d) Circular lines
      Answer: a) Always closed loops
34. A galvanometer can be used as an ammeter by:
    • a) Connecting a low resistance in series
    • b) Connecting a high resistance in series
    • c) Connecting a low resistance in parallel
    • d) Connecting a high resistance in parallel
      Answer: a) Connecting a low resistance in series
35. The magnetic field strength is maximum inside:
    • a) A bar magnet
    • b) A solenoid
    • c) A toroid
    • d) A current-carrying wire
      Answer: b) A solenoid
36. The flux linkage is:
    • a) The product of magnetic flux and number of turns in a coil
    • b) The product of magnetic field and area
    • c) The ratio of flux to area
    • d) The rate of change of magnetic flux
      Answer: a) The product of magnetic flux and number of turns in a coil
37. The force on a current-carrying conductor placed in a magnetic field is given by:
    • a) F=BILsin⁡θF = BIL \sin \thetaF=BILsinθ
    • b) F=BILcos⁡θF = BIL \cos \thetaF=BILcosθ
    • c) F=B×IF = B \times IF=B×I
    • d) F=BILF = BILF=BIL
      Answer: a) F=BILsin⁡θF = BIL \sin \thetaF=BILsinθ
38. The magnetic field inside a current-carrying solenoid is:
    • a) Non-uniform
    • b) Uniform
    • c) Zero
    • d) Radial
      Answer: b) Uniform
39. A transformer works on the principle of:
    • a) Electromagnetic Induction
    • b) Electrostatic Induction
    • c) Thermoelectric Induction
    • d) Magnetic Induction
      Answer: a) Electromagnetic Induction
40. The magnetic flux through a surface is zero when:
    • a) The surface is perpendicular to the magnetic field
    • b) The surface is parallel to the magnetic field
    • c) The magnetic field is zero
    • d) The surface area is zero
      Answer: b) The surface is parallel to the magnetic field
41. The magnetic field produced by a current-carrying solenoid is:
    • a) Zero inside the solenoid
    • b) Uniform inside the solenoid
    • c) Non-uniform inside the solenoid
    • d) Uniform outside the solenoid
      Answer: b) Uniform inside the solenoid
42. The induced EMF in a coil is directly proportional to:
    • a) The rate of change of magnetic field
    • b) The area of the coil
    • c) The number of turns in the coil
    • d) The resistance of the coil
      Answer: a) The rate of change of magnetic field
43. The magnetic field lines inside a current-carrying solenoid are:
    • a) Closed loops running from south to north
    • b) Circular around the wire
    • c) Radial lines
    • d) Uniform and parallel to the axis
      Answer: d) Uniform and parallel to the axis
44. In a moving coil galvanometer, the magnetic field is:
    • a) Radial
    • b) Uniform
    • c) Varying
    • d) Zero
      Answer: b) Uniform
45. The magnetic field due to a long straight current-carrying wire decreases with:
    • a) Distance from the wire
    • b) Time
    • c) Current
    • d) Temperature
      Answer: a) Distance from the wire
46. The magnetic force on a current-carrying conductor is greatest when:
    • a) The conductor is parallel to the magnetic field
    • b) The conductor is perpendicular to the magnetic field
    • c) The conductor is at an angle of 45 degrees to the magnetic field
    • d) The magnetic field is zero
      Answer: b) The conductor is perpendicular to the magnetic field
47. In an electric motor, the coil rotates due to:
    • a) The torque produced by the interaction of the magnetic field and the current
    • b) The force of gravity
    • c) The electric field
    • d) The thermal expansion
      Answer: a) The torque produced by the interaction of the magnetic field and the current
48. The magnetic field inside a toroid is:
    • a) Non-uniform
    • b) Zero
    • c) Uniform and parallel to the axis
    • d) Uniform and circular
      Answer: d) Uniform and circular
49. The phenomenon of electromagnetic induction is used in:
    • a) Generators
    • b) Motors
    • c) Transformers
    • d) All of the above
      Answer: d) All of the above
50. The electromotive force (EMF) induced in a coil is given by:
    • a) E=−dΦdtE = -\frac{d\Phi}{dt}E=−dtdΦ​
    • b) E=dΦdtE = \frac{d\Phi}{dt}E=dtdΦ​
    • c) E=B×vE = B \times vE=B×v
    • d) E=B×AE = B \times AE=B×A
      Answer: a) E=−dΦdtE = -\frac{d\Phi}{dt}E=−dtdΦ​
51. The direction of magnetic field lines inside a magnet is from:
    • a) South to North
    • b) North to South
    • c) East to West
    • d) West to East
      Answer: b) North to South
52. The magnetic field produced by a solenoid can be strengthened by:
    • a) Increasing the number of turns in the coil
    • b) Decreasing the current
    • c) Increasing the length of the solenoid
    • d) Reducing the cross-sectional area
      Answer: a) Increasing the number of turns in the coil
53. The magnetic force between two current-carrying conductors is:
    • a) Attractive if currents are in opposite directions
    • b) Repulsive if currents are in the same direction
    • c) Attractive if currents are in the same direction
    • d) Zero if currents are equal
      Answer: c) Attractive if currents are in the same direction
54. The unit of magnetic flux is:
    • a) Weber
    • b) Tesla
    • c) Ampere
    • d) Ohm
      Answer: a) Weber
55. The magnetic field due to a current-carrying solenoid is:
    • a) Radial
    • b) Uniform inside and non-uniform outside
    • c) Non-uniform inside and uniform outside
    • d) Uniform everywhere
      Answer: b) Uniform inside and non-uniform outside
56. The strength of the magnetic field inside a solenoid can be increased by:
    • a) Increasing the current
    • b) Decreasing the number of turns
    • c) Increasing the length of the solenoid
    • d) Using a thinner wire
      Answer: a) Increasing the current
57. The principle behind a moving coil meter is:
    • a) Electromagnetic Induction
    • b) Electromagnetic Force
    • c) Electromagnetic Radiation
    • d) Electromagnetic Wave
      Answer: b) Electromagnetic Force
58. The direction of the induced EMF in a coil is such that:
    • a) It opposes the change in magnetic flux
    • b) It enhances the change in magnetic flux
    • c) It is perpendicular to the magnetic field
    • d) It is directly proportional to the magnetic flux
      Answer: a) It opposes the change in magnetic flux
59. The magnetic field lines inside a current-carrying solenoid are:
    • a) Non-uniform and circular
    • b) Uniform and parallel to the axis
    • c) Circular around the wire
    • d) Radial
      Answer: b) Uniform and parallel to the axis
60. The magnetic field at the center of a circular loop is:
    • a) Zero
    • b) Directly proportional to the radius of the loop
    • c) Inversely proportional to the radius of the loop
    • d) Directly proportional to the current
      Answer: d) Directly proportional to the current
61. The SI unit of magnetic flux density is:
    • a) Tesla
    • b) Weber
    • c) Coulomb
    • d) Ampere
      Answer: a) Tesla
62. The phenomenon where a changing magnetic field induces an EMF is known as:
    • a) Electromagnetic Induction
    • b) Electrostatic Induction
    • c) Electromagnetic Radiation
    • d) Magnetic Resonance
      Answer: a) Electromagnetic Induction
63. The force on a current-carrying conductor in a magnetic field depends on:
    • a) The strength of the magnetic field
    • b) The length of the conductor
    • c) The current through the conductor
    • d) All of the above
      Answer: d) All of the above
64. The electromotive force (EMF) produced in a coil by electromagnetic induction is:
    • a) Directly proportional to the rate of change of current
    • b) Inversely proportional to the rate of change of magnetic flux
    • c) Directly proportional to the rate of change of magnetic flux
    • d) Inversely proportional to the number of turns in the coil
      Answer: c) Directly proportional to the rate of change of magnetic flux
65. The direction of the magnetic force on a moving charge is:
    • a) Parallel to the velocity of the charge
    • b) Perpendicular to the velocity of the charge
    • c) Parallel to the magnetic field
    • d) Opposite to the magnetic field
      Answer: b) Perpendicular to the velocity of the charge
66. The magnetic field inside a long solenoid is:
    • a) Uniform and parallel to the axis
    • b) Non-uniform and radial
    • c) Circular and perpendicular to the axis
    • d) Zero
      Answer: a) Uniform and parallel to the axis
67. The force on a current-carrying conductor in a magnetic field is given by:
    • a) F=BILsin⁡θF = BIL \sin \thetaF=BILsinθ
    • b) F=BILcos⁡θF = BIL \cos \thetaF=BILcosθ
    • c) F=BILsin⁡θF = \frac{BIL}{\sin \theta}F=sinθBIL​
    • d) F=BILF = BILF=BIL
      Answer: a) F=BILsin⁡θF = BIL \sin \thetaF=BILsinθ
68. The magnetic field strength (B) inside a toroid is:
    • a) Uniform and parallel to the axis
    • b) Non-uniform
    • c) Zero
    • d) Uniform and circular
      Answer: d) Uniform and circular
69. The SI unit of magnetic field strength is:
    • a) Tesla
    • b) Weber
    • c) Ampere
    • d) Henry
      Answer: a) Tesla
70. The force experienced by a current-carrying conductor in a magnetic field is:
    • a) Independent of the angle between the conductor and the magnetic field
    • b) Maximum when the angle is 90 degrees
    • c) Maximum when the angle is 0 degrees
    • d) Minimum when the angle is 90 degrees
      Answer: b) Maximum when the angle is 90 degrees
71. The magnetic field around a current-carrying conductor is:
    • a) Circular
    • b) Radial
    • c) Straight
    • d) Elliptical
      Answer: a) Circular
72. A current-carrying solenoid behaves like:
    • a) A bar magnet
    • b) An electromagnet
    • c) A permanent magnet
    • d) A capacitor
      Answer: b) An electromagnet
73. The direction of the magnetic field lines around a straight current-carrying conductor is:
    • a) Radial lines
    • b) Circular lines
    • c) Straight lines
    • d) Parallel lines
      Answer: b) Circular lines
74. The force between two parallel current-carrying conductors is:
    • a) Zero if currents are in opposite directions
    • b) Attractive if currents are in opposite directions
    • c) Repulsive if currents are in the same direction
    • d) Zero if currents are in the same direction
      Answer: b) Attractive if currents are in opposite directions
75. The magnetic field produced by a current-carrying wire can be increased by:
    • a) Increasing the current
    • b) Decreasing the distance from the wire
    • c) Increasing the length of the wire
    • d) Increasing the radius of the wire
      Answer: a) Increasing the current
76. The magnetic flux through a surface is defined as:
    • a) The product of magnetic field and area
    • b) The product of magnetic field and the length
    • c) The product of current and area
    • d) The product of electric field and area
      Answer: a) The product of magnetic field and area
77. The force on a moving charge in a magnetic field is:
    • a) Directly proportional to the speed of the charge
    • b) Directly proportional to the magnitude of the charge
    • c) Directly proportional to the strength of the magnetic field
    • d) All of the above
      Answer: d) All of the above
78. The unit of magnetic flux density (B) is:
    • a) Weber per square meter
    • b) Tesla per square meter
    • c) Newton per meter
    • d) Joule per coulomb
      Answer: a) Weber per square meter
79. The magnetic field strength produced by a solenoid is:
    • a) Directly proportional to the current
    • b) Directly proportional to the number of turns
    • c) Inversely proportional to the length of the solenoid
    • d) All of the above
      Answer: d) All of the above
80. The magnetic field lines inside a current-carrying toroid are:
    • a) Parallel to the axis
    • b) Radial
    • c) Circular
    • d) Uniform and straight
      Answer: c) Circular
81. The magnetic force on a current-carrying conductor is:
    • a) Maximum when the current is zero
    • b) Minimum when the magnetic field is zero
    • c) Independent of the current
    • d) Directly proportional to the length of the conductor
      Answer: d) Directly proportional to the length of the conductor
82. The direction of the magnetic force on a current-carrying wire can be found using:
    • a) Right-Hand Rule
    • b) Left-Hand Rule
    • c) Faraday’s Law
    • d) Lenz’s Law
      Answer: a) Right-Hand Rule
83. The magnetic field inside a current-carrying coil is:
    • a) Non-uniform
    • b) Uniform and parallel to the axis
    • c) Zero
    • d) Radial
      Answer: b) Uniform and parallel to the axis
84. The phenomenon of inducing a current by a changing magnetic field is known as:
    • a) Electromagnetic Induction
    • b) Electromagnetic Radiation
    • c) Electrostatic Induction
    • d) Magnetic Resonance
      Answer: a) Electromagnetic Induction
85. The magnetic field strength (B) around a straight current-carrying wire is:
    • a) Inversely proportional to the distance from the wire
    • b) Directly proportional to the distance from the wire
    • c) Zero inside the wire
    • d) Uniform everywhere
      Answer: a) Inversely proportional to the distance from the wire
86. The magnetic flux (Φ) is given by:
    • a) Φ=B×A×cos⁡θ\Phi = B \times A \times \cos \thetaΦ=B×A×cosθ
    • b) Φ=B×A×sin⁡θ\Phi = B \times A \times \sin \thetaΦ=B×A×sinθ
    • c) Φ=B×A\Phi = B \times AΦ=B×A
    • d) Φ=B×cos⁡θ\Phi = B \times \cos \thetaΦ=B×cosθ
      Answer: a) Φ=B×A×cos⁡θ\Phi = B \times A \times \cos \thetaΦ=B×A×cosθ
87. The SI unit of magnetic flux is:
    • a) Weber
    • b) Tesla
    • c) Henry
    • d) Coulomb
      Answer: a) Weber
88. The magnetic field produced by a current-carrying wire is:
    • a) Radial
    • b) Circular
    • c) Linear
    • d) Elliptical
      Answer: b) Circular
89. The principle behind electromagnetic induction is:
    • a) Faraday’s Law
    • b) Lenz’s Law
    • c) Ampère’s Law
    • d) Gauss’s Law
      Answer: a) Faraday’s Law
90. The magnetic field at the center of a circular current-carrying loop is:
    • a) Inversely proportional to the radius of the loop
    • b) Directly proportional to the radius of the loop
    • c) Zero
    • d) Directly proportional to the current and inversely proportional to the radius
      Answer: d) Directly proportional to the current and inversely proportional to the radius
91. The magnetic field produced by a solenoid is:
    • a) Zero inside and non-zero outside
    • b) Uniform inside and non-uniform outside
    • c) Non-uniform inside and uniform outside
    • d) Non-uniform everywhere
      Answer: b) Uniform inside and non-uniform outside
92. The magnetic field strength inside a solenoid can be increased by:
    • a) Increasing the number of turns per unit length
    • b) Increasing the length of the solenoid
    • c) Decreasing the current
    • d) Using a non-ferromagnetic core
      Answer: a) Increasing the number of turns per unit length
93. The direction of magnetic field lines around a current-carrying wire is:
    • a) Radial outward
    • b) Radial inward
    • c) Circular
    • d) Parallel
      Answer: c) Circular
94. The magnetic field strength due to a current-carrying wire is:
    • a) Directly proportional to the current
    • b) Inversely proportional to the distance from the wire
    • c) Directly proportional to the length of the wire
    • d) Both a and b
      Answer: d) Both a and b
95. The magnetic field at the center of a solenoid is:
    • a) Zero
    • b) Uniform and parallel to the axis
    • c) Non-uniform and radial
    • d) Non-uniform and circular
      Answer: b) Uniform and parallel to the axis
96. The force between two parallel current-carrying conductors is:
    • a) Directly proportional to the distance between them
    • b) Inversely proportional to the distance between them
    • c) Directly proportional to the current in each conductor
    • d) Both b and c
      Answer: d) Both b and c
97. The magnetic field inside a current-carrying toroid is:
    • a) Uniform and circular
    • b) Non-uniform and radial
    • c) Zero
    • d) Uniform and parallel to the axis
      Answer: a) Uniform and circular
98. The force on a charged particle moving in a magnetic field is maximum when:
    • a) The velocity of the particle is zero
    • b) The angle between the velocity and the magnetic field is 90 degrees
    • c) The magnetic field strength is zero
    • d) The particle is stationary
      Answer: b) The angle between the velocity and the magnetic field is 90 degrees
99. The magnetic flux through a surface is:
    • a) The product of the magnetic field and the distance from the surface
    • b) The product of the magnetic field and the length of the surface
    • c) The product of the magnetic field and the area of the surface
    • d) The product of the electric field and the area of the surface
      Answer: c) The product of the magnetic field and the area of the surface
100. The magnetic field due to a current-carrying loop is: – a) Uniform at all points in space – b) Maximum at the center of the loop – c) Zero at the center of the loop – d) Directly proportional to the radius of the loop
     Answer: b) Maximum at the center of the loop