Basic Qualification · B-005 Basic electronics and theory · B-005-011-006
Maximum induced voltage in a coil occurs when:
- A the current through the coil is DC
- B current is going through its least rate change
- C the magnetic field around the coil is not changing
- D current is going through its greatest rate of change
Correct answer: D — current is going through its greatest rate of change. From the official ISED question bank, verified word for word.
Why
Voltage is induced in a coil only when the magnetic field around it changes, and that field changes fastest when the electric current flowing through the coil changes most rapidly. The full explanation — and one for every question — is in Pro.
Practise this section
The theory: Ohm's law, power, series and parallel circuits, AC and DC, frequency and wavelength, decibels, and the metric prefixes the exam leans on.