GED Science TestPhysical ScienceMedium
A student is designing an experiment to demonstrate the generation of an electric current using a changing magnetic field. Which of the following principles is most relevant to this experiment?
- AOhm's Law
- BAmpere's Law
- CFaraday's Law of Induction
- DCoulomb's Law
Show answer & explanationAnswer & explanation
Correct answer: C. Faraday's Law of Induction
Faraday's Law of Induction states that a changing magnetic field through a coil of wire will induce an electromotive force (and thus a current) in the wire. This is the fundamental principle behind generators.
Why the other options are wrong
- A. Ohm's Law relates voltage, current, and resistance in an electrical circuit (V=IR).
- B. Ampere's Law relates the magnetic field to the electric current that produces it.
- D. Coulomb's Law describes the force between two stationary electric charges.
Faraday's Law of Induction
States that a changing magnetic flux through a circuit induces an electromotive force (EMF), which in turn drives an electric current.
- Foundation of electric generators and transformers.
- Requires relative motion between a conductor and a magnetic field.
- Magnitude of induced EMF is proportional to the rate of change of magnetic flux.
Memory trick: Electromagnetism's laws: current makes fields, fields make current, charges attract and repel.