Free Faraday's Law MCQs with Answers
48 Faraday's Law MCQs from Physics, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
Faraday's law states that an induced electromotive force equals the rate of change of magnetic flux linkage through a circuit. Questions cover changing field, area, angle or motion, the negative sign associated with Lenz's law, and the distinction between induced emf and the current that may flow in a closed circuit.
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48 questions · page 2 of 3
- A. 1 V
- B. 1.5 V
- C. 0.1 V
- D. 0.15 V
Explanation: We can use Faraday's law of induction; emf=−N(ΔΦ/Δt )The change in magnetic flux (ΔΦ) is:ΔΦ=Φfinal −Φinitia = (2×10−4 Wb)−(6×10−4 Wb) =…
Correct answer: 1 V- A. Zero
- B. Maximum
- C. ϵ = L(∆ I/ ∆t)
- D. ϵ =- L(∆ I/ ∆t)
Explanation: The magnitude of self-induced electromotive force (emf) in a coil, also known as back emf, is given by Faraday's law of electromagnetic…
Correct answer: Zero- A. It does not have any effect.
- B. It reverses the direction of current.
- C. It increases the current in the motor.
- D. It decreases the current in the motor.
Explanation: Because the back e.m.f. acts in opposition to the supply voltage, the net voltage across the motor's windings is the difference between…
Correct answer: It decreases the current in the motor.- A. cuts the magnetic flux.
- B. follows the path of magnetic flux.
- C. moves parallel to the magnetic field.
- D. moves perpendicular to the magnetic field.
Explanation: Faraday's law of electromagnetic induction states that an electromotive force (e.m.f.) is induced in a conductor when there is a change in…
Correct answer: cuts the magnetic flux.- A. low resistivity.
- B. decrease the area.
- C. strong magnetic field.
- D. increase the thickness.
Explanation: Eddy currents result in power loss in conducting materials due to the resistance encountered by the circulating currents.
Correct answer: increase the thickness.- A. placed in an electric field.
- B. moved in an electric field.
- C. placed in a magnetic field.
- D. moved in a magnetic field.
Explanation: The correct answer is Option D. When a coil is moved in a magnetic field, the magnetic flux through the coil changes, inducing an…
Correct answer: moved in a magnetic field.- A. low
- B. high
- C. varying
- D. constant
Explanation: The correct answer is Option C: varying. According to Faraday's law of electromagnetic induction, an electromotive force is induced in a…
Correct answer: varying28. If an electric motor is overloaded, then the magnitude of back electromotive force (e.m.f.) will
- A. increase
- B. decrease
- C. become zero
- D. remain the same
Explanation: When an electric motor is overloaded, it slows down due to the increased load.
Correct answer: decrease- A. Self-induction.
- B. Self-inductance.
- C. Mutual induction.
- D. Mutual inductance.
Explanation: The correct answer is mutual induction. This process involves the induction of electromotive force (EMF) in one coil due to a changing…
Correct answer: Mutual induction.- A. Lenz's law.
- B. Faraday's law.
- C. Ampere's law.
- D. Coulomb's law.
Explanation: The principle of an alternating current generator is based on Faraday's law of electromagnetic induction.
Correct answer: Faraday's law.- A. 0
- B. 1
- C. Less than 0
- D. More than 1
Explanation: The self-inductance of a straight wire carrying current is 0 because self-inductance arises from the wire's ability to create a magnetic…
Correct answer: 0- A. Force
- B. Magnetic field
- C. Induced current
- D. Electric field
Explanation: Fleming's right-hand rule gives which direction the current flows. The right hand is held with the thumb, index finger and middle finger…
Correct answer: Force- A. Force
- B. Induced current
- C. Magnetic field
- D. Motion
Explanation: Lenz's law states that the direction of the induced current in a circuit is such that it opposes the change in magnetic flux, which is a…
Correct answer: Induced current- A. Mechanical energy into electrical energy
- B. Chemical energy into mechanical energy
- C. Sound energy into mechanical energy
- D. Electrical energy into mechanical energy
Explanation: A current generator, generates current by converting mechanical energy into electrical energy.
Correct answer: Mechanical energy into electrical energy- A. Inertia
- B. Force
- C. Energy
- D. Momentum
Explanation: Just like inertia tends to maintain its original state of motion or rest.
Correct answer: Inertia- A. First increases and then becomes zero
- B. First increases and then becomes constant at some value
- C. Increases with the passage of time
- D. Remains zero
Explanation: Explanation:At that instant when the switch is closed momentarily current flows through the secondary coil due to change in magnetic flux.
Correct answer: First increases and then becomes zero- A. 2.5V
- B. 25V
- C. 250V
- D. 0.25V
Explanation: According to faraday's law of electromagnetic induction, whenever there is change in magnetic flux, in this particular case there's change…
Correct answer: 25V- A. 10 V
- B. 12 V
- C. 14 V
- D. 16 V
Explanation: Given: Magnetic field strength = B = 0.6 T Length = L = 1m Velocity = v = 20 m/s emf = ε = ?
Correct answer: 12 V- A. NmA-2s-1
- B. NmAs-1
- C. NmA-1s-1
- D. NmA-2s1
Explanation: The unit of magnetic flux change (∆Φ) is measured in webers (Wb), and the unit of time change (∆t) is measured in seconds.
Correct answer: NmA-1s-1- A. Rotated about a north-south axis
- B. Rotated about an east-west axis
- C. Moved rapidly, without rotation toward the east
- D. Moved rapidly, without rotation toward the south
Explanation: When the copper hoop is rotated about an east-west axis, the maximum induced emf is produced.
Correct answer: Rotated about an east-west axis