Non-Destructive Testing (NDT) Practice Test

What term is used to describe the phenomenon when one circuit induces current flow in a second nearby circuit?

1. Electromagnetic induction

2. Resistance fluctuation

3. Mutual inductance

4. Conductive interaction

The correct answer is: Mutual inductance

The phenomenon when one circuit induces current flow in a second nearby circuit is best described as mutual inductance. This term specifically refers to the ability of one electrical circuit to influence another through its magnetic field. When an alternating current (AC) flows through the first circuit, it creates a changing magnetic field around it. If a second circuit is located within this magnetic field, the change can induce an electromotive force (EMF) in the second circuit, leading to current flow. Mutual inductance is a key principle in many electrical devices, such as transformers, where it enables the transfer of energy between circuits through magnetic coupling. It highlights the relationship between two coils and how the change in current in one coil can affect the other. Understanding this phenomenon is important for applications in non-destructive testing (NDT) techniques that rely on electromagnetic principles, such as eddy current testing, where the interaction between currents in conductive materials can reveal material properties and integrity.