Basic Qualification · B-005 Basic electronics and theory · B-005-011-005
The strength of the magnetic field around a conductor in air is:
- A directly proportional to the current in the conductor
- B inversely proportional to the diameter of the conductor
- C directly proportional to the diameter of the conductor
- D inversely proportional to the voltage on the conductor
Correct answer: A — directly proportional to the current in the conductor. From the official ISED question bank, verified word for word.
Why
The magnetic field around a wire gets stronger exactly as the electric current flowing through it increases, meaning if you double the current, you double the field strength. 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.