13.1 Electromagnetic Induction and Faraday’s Law

Cards (58)

  • What is produced by electromagnetic induction?
    Voltage or induced current
  • The negative sign in Faraday’s Law reflects Lenz’s Law, which states that the direction of the induced EMF opposes the change in magnetic flux
  • Electromagnetic induction is fundamental to devices like transformers and generators
  • What is the primary requirement for inducing an electric field in electromagnetic induction?
    A changing magnetic field
  • Magnetic flux is calculated using the formula: \(\Phi_B = B \cdot A \cdot \cos{\theta}\), where \(\theta\) is the angle between the magnetic field and the normal to the surface
  • What do transformers use to step up or down voltages?
    Mutual inductance
  • Transformers convert alternating current (AC) between circuits.
    True
  • What is the key equation for the EMF induced in a generator?
    \mathcal{E} = NBAω \sin(ωt)</latex>
  • What is a key requirement for electromagnetic induction to occur?
    A changing magnetic field
  • What does magnetic flux measure?
    The number of magnetic field lines
  • What is magnetic flux measured in?
    Webers (Wb)
  • What does magnetic flux measure?
    Magnetic field lines
  • The angle \(\theta\) in the magnetic flux equation is between the magnetic field and the normal to the surface.

    True
  • The EMF induced in a generator coil is given by \(\mathcal{E} = NBAω \sin(ωt)\).

    True
  • Which of Maxwell's equations is derived from Faraday's Law?
    \(\nabla \times \mathbf{E} = -\frac{\partial \mathbf{B}}{\partial t}\)
  • What generates a voltage or induced current in electromagnetic induction?
    Electric field
  • Match the component in Faraday’s Law with its unit:
    \(\mathcal{E}\) ↔️ Volts (V)
    \(N\) ↔️ None
    \(\Phi_B\) ↔️ Webers (Wb)
    \(\frac{d\Phi_B}{dt}\) ↔️ Webers per second (Wb/s)
  • What is the unit of surface area in the magnetic flux formula?
    Square meters (m\(^2\))
  • What type of energy do generators convert mechanical energy into?
    Electrical energy
  • Generators use rotating coils to convert mechanical energy into electrical energy.
  • What magnetic field opposes the approaching magnet in Lenz's Law?
    The induced magnetic field
  • What mathematical equation represents Faraday's Law?
    E=\mathcal{E} =−NdΦBdt - N \frac{d\Phi_{B}}{dt}
  • What is induced electromotive force (EMF) measured in?
    Volts (V)
  • Lenz’s Law states that the induced EMF opposes the change in magnetic flux that produces it.

    True
  • In the magnetic flux equation, \(B\) represents the magnetic field strength in teslas.
  • What do transformers utilize to step up or down voltages?
    Mutual inductance
  • Faraday's Law determines the magnitude of induced EMF, while Lenz's Law determines its direction.
    True
  • Match the Maxwell's equation with its relevance to Faraday's Law:
    Faraday's Law of Induction ↔️ Forms a core equation
    Ampère-Maxwell Law ↔️ Accounts for magnetic fields created by changing electric fields
  • A changing magnetic field is required for electromagnetic induction.
    True
  • What are the units of induced EMF in Faraday’s Law?
    Volts
  • Match the component in Faraday’s Law with its definition:
    \(\mathcal{E}\) ↔️ Induced electromotive force
    N ↔️ Number of turns
    \(\Phi_B\) ↔️ Magnetic flux
    \(\frac{d\Phi_B}{dt}\) ↔️ Rate of change of magnetic flux
  • Moving a magnet through a coil of wire induces a current due to electromagnetic induction.

    True
  • The magnetic field strength \(B\) in the magnetic flux formula is measured in teslas (T).

    True
  • The key equation for transformers is: \(V_p / V_s = N_p / N_s\), where \(V\) is voltage and \(N\) is the number of turns
  • What is the key equation for transformers relating primary and secondary voltages and number of turns?
    \frac{V_p}{V_s} = \frac{N_p}{N_s}</latex>
  • Lenz's Law states that the direction of the induced EMF opposes the change in magnetic flux.
  • Current flows in electromagnetic induction only if there is a closed loop.

    True
  • Magnetic flux is calculated using the equation \Phi_B = B \cdot A \cdot \cos{\theta}.
  • The rate of change of magnetic flux is measured in webers per second.
  • The magnetic flux equation is \(\Phi_B = B \cdot A \cdot \cos{\theta}\).

    True