What is the process called when a changing magnetic field induces voltage in a coil?

What is the process called when a changing magnetic field induces voltage in a coil?

• A. Electromagnetic induction
• B. Magnetic resonance
• C. Dielectric polarization
• D. Capacitive coupling

Answer: (A)

Electromagnetic induction is the process where a changing magnetic field through a coil creates an electric voltage in that coil. This works because the magnetic flux through the coil is changing over time, and Faraday’s law states that the induced EMF is proportional to the rate of change of that flux (with a negative sign indicating the induced current opposes the change, per Lenz’s law). This principle is what powers generators and transformers—by moving a magnet or varying the current in a nearby coil, you change the magnetic field linked to the coil and voltage appears. The other terms don’t fit this situation: magnetic resonance involves energy transfer at specific magnetic-field-resonant frequencies; dielectric polarization describes how insulators align their dipoles in response to an electric field; and capacitive coupling refers to signal transfer between conductors through a capacitor. None of these describe voltage being generated in a coil due to a changing magnetic field.

Electromagnetic induction is the process where a changing magnetic field through a coil creates an electric voltage in that coil. This works because the magnetic flux through the coil is changing over time, and Faraday’s law states that the induced EMF is proportional to the rate of change of that flux (with a negative sign indicating the induced current opposes the change, per Lenz’s law). This principle is what powers generators and transformers—by moving a magnet or varying the current in a nearby coil, you change the magnetic field linked to the coil and voltage appears.

The other terms don’t fit this situation: magnetic resonance involves energy transfer at specific magnetic-field-resonant frequencies; dielectric polarization describes how insulators align their dipoles in response to an electric field; and capacitive coupling refers to signal transfer between conductors through a capacitor. None of these describe voltage being generated in a coil due to a changing magnetic field.