7.3.3 Graphs of Potential Difference in the Coil

• What is the relationship between potential difference and magnetic flux in a coil according to Faraday's Law?

  The potential difference across a coil varies with the rate of change of magnetic flux through the coil.
• What does a Voltage vs. Time graph represent in the context of electromagnetic induction?

  • It shows the potential difference across a coil as a magnet moves through it.
  • Peaks occur when the magnet enters or exits the coil.
  • Zero voltage is observed when the magnet is stationary.
• What happens to the induced EMF when a magnet enters or exits a coil?

  There is a rapid change in magnetic flux, resulting in a high induced EMF (peak voltage).
• What is the induced EMF when the magnet is stationary within or outside the coil?

  The induced EMF drops to zero when the magnet is stationary.
• What does a Voltage vs. Rate of Change of Magnetic Flux graph illustrate?

  • It shows the potential difference as the rate of change of magnetic flux is varied.
  • Typically presents a straight line indicating a linear relationship.
  • The induced EMF is directly proportional to the rate of change of magnetic flux.
• What is the formula for induced EMF according to Faraday's Law of Induction?


  \(\text{EMF} = -\frac{\Delta \Phi}{\Delta t}\)
• What does Lenz's Law state about the direction of induced EMF?

  Lenz's Law states that the direction of the induced EMF will always oppose the change in magnetic flux.
• How is magnetic flux defined?

  Magnetic flux (\(\Phi\)) is the product of the magnetic field strength (\(B\)), area (\(A\)), and the cosine of the angle (\(\theta\)) between the field lines and the normal to the surface.
• What is the formula for magnetic flux?

  \(\Phi = B \times A \times \cos(\theta)\)
• What are the characteristics of the graph when a magnet is rapidly moved through a coil?

  • The voltage graph shows a sharp spike corresponding to the magnet’s entry and exit.
  • The spikes represent the rapid change in magnetic flux.
  • High induced EMF is produced during these spikes.
• What does a sinusoidal voltage output indicate when a coil is placed in a varying magnetic field?

  • It reflects the varying rate of change of magnetic flux.
  • The magnetic field strength is being varied sinusoidally (AC magnetic field).
  • The sinusoidal shape corresponds to the alternating nature of the magnetic field.
• What factors affect the graphs of potential difference in a coil?

  • Rate of change of magnetic flux: Faster changes result in higher induced voltages.
  • Strength of magnetic field: A stronger field or faster-moving magnet increases the rate of change of flux.
• What equipment is typically used to measure induced voltage across a coil in experiments?

  • Voltmeter
  • Oscilloscope
• What is the overall significance of understanding graphs of potential difference in a coil?

  • They demonstrate how voltage changes with varying magnetic flux.
  • They illustrate key principles based on Faraday’s Law and Lenz’s Law.
  • They help visualize how electromagnetic induction works in practical applications.