Which law relates induced emf to rate of change of magnetic flux?

Which law relates induced emf to rate of change of magnetic flux?

• A. Ohm's law
• B. Ampere's law
• C. Faraday's law
• D. Gauss's law

Answer: (C)

The main idea is electromagnetic induction: a changing magnetic flux through a circuit induces an electric emf. Faraday’s law captures this, stating that the induced emf equals the negative rate of change of the magnetic flux, ε = -dΦ/dt. The flux Φ depends on the magnetic field, the area of the loop, and the orientation, so any change in these factors over time produces a voltage. The minus sign is Lenz’s law, meaning the induced emf acts to oppose the change in flux. The other laws describe different relationships—Ohm’s law links voltage, current, and resistance; Ampère’s law relates magnetic fields to currents; Gauss’s law links electric flux to charge. So the law that specifically ties induced emf to the rate of change of magnetic flux is Faraday’s law.

The main idea is electromagnetic induction: a changing magnetic flux through a circuit induces an electric emf. Faraday’s law captures this, stating that the induced emf equals the negative rate of change of the magnetic flux, ε = -dΦ/dt. The flux Φ depends on the magnetic field, the area of the loop, and the orientation, so any change in these factors over time produces a voltage. The minus sign is Lenz’s law, meaning the induced emf acts to oppose the change in flux. The other laws describe different relationships—Ohm’s law links voltage, current, and resistance; Ampère’s law relates magnetic fields to currents; Gauss’s law links electric flux to charge. So the law that specifically ties induced emf to the rate of change of magnetic flux is Faraday’s law.