7.3.1 Electromagnetic (EM) Induction

• What is electromagnetic induction?

  It is the process of generating an electric current in a conductor by changing the magnetic field around it.
• What are the key concepts underlying electromagnetic induction?

  • Faraday’s Law of Electromagnetic Induction
  • Lenz’s Law
• What does Faraday’s Law of Electromagnetic Induction state?

  The induced electromotive force (EMF) in a circuit is directly proportional to the rate of change of magnetic flux through the circuit.
• What is the formula for calculating induced EMF according to Faraday’s Law?


  $\text{EMF} =$$-\frac{\Delta \Phi}{\Delta t}$
• What does \(\Delta \Phi\) represent in Faraday's Law?

  \(\Delta \Phi\) represents the change in magnetic flux.
• What does Lenz’s Law state?

  The direction of the induced current is such that it opposes the change in magnetic flux that caused it.
• Why is Lenz’s Law important in electromagnetic induction?

  It ensures the conservation of energy by opposing changes in magnetic flux.
• What are the key factors affecting electromagnetic induction?

  1. Magnetic Field Strength

  2. Rate of Change of Magnetic Flux

  3. Number of Turns in the Coil

  4. Area of the Coil
• How does magnetic field strength affect induced EMF?

  A stronger magnetic field will induce a larger EMF in the conductor.
• What happens to the induced EMF if the rate of change of magnetic flux increases?

  The induced EMF will also increase.
• How does increasing the number of turns in a coil affect induced EMF?

  Increasing the number of turns in a coil will increase the induced EMF.
• What effect does the area of the coil have on induced EMF?

  A larger coil area exposed to the magnetic field will result in a greater induced EMF.
• What are some demonstrations of electromagnetic induction?

  1. Moving a magnet through a coil

  2. Changing magnetic field around a stationary coil
• What happens when a magnet is moved in and out of a coil of wire?

  It induces an EMF in the coil, and the direction of the induced current changes depending on the movement.
• What is the result of varying the strength of a magnetic field around a stationary coil?

  The EMF induced is proportional to the rate of change of the magnetic field strength.
• What are some applications of electromagnetic induction?

  1. Generators

  2. Transformers

  3. Induction Cooktops

  4. Electric Guitars
• How do generators utilize electromagnetic induction?

  Mechanical energy is used to rotate a coil within a magnetic field, inducing an EMF and generating electrical power.
• How do transformers work in relation to electromagnetic induction?

  AC current in the primary coil creates a changing magnetic field that induces a voltage in the secondary coil.
• How do induction cooktops utilize electromagnetic induction?

  An alternating current creates a changing magnetic field in the cooktop, inducing currents in the metal pan and heating it.
• How do electric guitars use electromagnetic induction?

  String vibrations cause changes in the magnetic field around the pickups, inducing a current that is converted into an electrical signal.
• What is an example of an experiment demonstrating Faraday's Law in practice?

  1. Connect a coil of wire to a galvanometer or voltmeter.

  2. Move a magnet in and out of the coil.

  3. Observe the induced current or voltage on the meter.

  4. Change the speed of the magnet’s movement, strength of the magnet, or number of coil turns to see effects on induced EMF.
• What is the summary of electromagnetic induction?

  • Process of generating an electric current by changing the magnetic field around a conductor.
  • Faraday’s Law: Induced EMF is proportional to the rate of change of magnetic flux.
  • Lenz’s Law: Direction of induced current opposes change in magnetic flux.
  • Key factors: Magnetic field strength, rate of change, number of coil turns, and coil area affect induced EMF.
  • Applications: Found in generators, transformers, induction cooktops, and various technologies.