Which law states that the induced voltage in a coil is proportional to the rate of change of the magnetic field?

The statement that the induced voltage in a coil is proportional to the rate of change of the magnetic field is encapsulated in Faraday's Law of Electromagnetic Induction. This law asserts that a change in magnetic flux through a coil of wire induces an electromotive force (EMF) in that coil. Mathematically, it can be expressed as EMF = -dΦ/dt, where Φ represents magnetic flux and t represents time. The negative sign indicates the direction of the induced voltage opposes the change in flux, adhering to Lenz's Law.

Understanding Faraday's Law is crucial because it fundamentally describes how electromagnetic induction works, which is a key principle behind the operation of many electrical devices, including generators and transformers. This concept underscores the relationship between electricity and magnetism, highlighting how a changing magnetic field can produce electrical energy.