Basic Qualification · B-005 Basic electronics and theory · B-005-004-009
What voltage is needed to supply a current of 200 milliamperes to operate a relay that has a resistance of 25 ohms?
- A 8 volts
- B 0.5 volts
- C 50 volts
- D 5 volts
Correct answer: D — 5 volts. From the official ISED question bank, verified word for word.
Why
To find the needed voltage, multiply the current by the resistance. 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.