12.3 Electromagnetic Induction

• A changing magnetic field is required for electromagnetic induction
• For electromagnetic induction, a changing magnetic field is required.
• The minus sign in Faraday's Law indicates opposition to the change in magnetic flux, as described by Lenz's Law


  True
• What happens to the magnetic flux when a magnet moves towards a coil?

  It increases
• What is stated by Faraday's Law of Induction?

  A changing magnetic field induces an EMF
• What is the key property of the magnetic field in Faraday's Law?

  Strength and rate of change
• The minus sign in Faraday's Law indicates that the induced EMF opposes the change in magnetic flux.

  True
• Comparison between Faraday's Law and Lenz's Law

  1️⃣ Faraday's Law focuses on the magnitude of induced EMF

  2️⃣ Lenz's Law focuses on the direction of induced EMF
• What is the principle behind the operation of generators?

  Electromagnetic induction
• What happens to the induced EMF in a generator if the magnetic field is stronger?

  It increases
• What principle do generators use to convert mechanical energy into electrical energy?

  Electromagnetic induction
• A stronger magnetic field in a generator produces a higher induced EMF.

  True
• The induced EMF in a generator depends on the magnetic field, flux changes, and conductor design.

  True
• The transformer equation is $\frac{V_{s}}{V_{p}} =$$\frac{N_{s}}{N_{p}}$


  True
• Transformers are used in power distribution systems to transmit electricity efficiently over long distances.


  True
• Match the aspect of electromagnetic induction with its description:

  Magnetic Field ↔️ A changing field is required

  Conductor ↔️ The induced EMF is generated here

  Induced EMF ↔️ Voltage produced by the field

  Faraday's Law ↔️ $\varepsilon =$$- N \frac{\Delta \Phi}{\Delta t}$
• The negative sign in Faraday's Law indicates that the induced EMF opposes the change in magnetic flux
• According to Lenz's Law, what counters the increase in magnetic flux when a magnet moves towards a coil?

  Induced current
• What is the term for the total magnetic field passing through the conductor in Lenz's Law?

  Magnetic flux
• When a magnet moves towards a coil, the induced current generates a magnetic field opposing the increase in magnetic flux.


  True
• The faster the magnetic flux changes over time, the greater the induced EMF.


  True
• As a conductor moves through a magnetic field, the changing magnetic flux induces an EMF.
• Transformers use alternating current (AC) to change voltage.


  True
• A step-up transformer increases the voltage.
• A conductor must be present for electromagnetic induction to occur


  True
• Match the key aspect of electromagnetic induction with its description:

  Magnetic Field ↔️ Changing magnetic field is required

  Conductor ↔️ Must be a conductive material

  Induced EMF ↔️ Voltage produced by changing magnetic field

  Faraday's Law ↔️ $\varepsilon =$$- N \frac{\Delta \Phi}{\Delta t}$
• What does Lenz's Law state about the direction of induced EMF?

  It opposes the change in flux
• A static magnetic field is sufficient for electromagnetic induction

  False
• The magnitude of the induced EMF depends on the rate of change of magnetic flux
• The rate of change of magnetic flux is denoted by $\Delta \Phi / \Delta t$
• What does Lenz's Law state about the induced EMF?

  It opposes the change in flux
• What does Lenz's Law dictate when a magnet moves towards a coil?

  Induced field opposes the motion
• In a generator, a conductor is rotated within a magnetic field
• Increasing the number of turns in a conductor in a generator increases the induced EMF.

  True
• In a generator, a conductor is rotated within a magnetic field
• How does the rate of change of magnetic flux affect the induced EMF in a generator?

  Faster changes increase EMF
• What are the two coils in a transformer called?

  Primary and secondary
• What is the definition of electromagnetic induction?

  Changing magnetic field induces EMF
• Faraday's Law states that the induced EMF is directly proportional to the rate of change of magnetic flux.


  True
• What does Lenz's Law state about the direction of the induced EMF?

  Opposes the change in flux