Basic Qualification · B-005 Basic electronics and theory · B-005-006-008
How much current is drawn by a 12-volt, 30-watt light bulb?
- A0.4 amperes
- B2.5 amperes
- C18 amperes
- D4.8 amperes
Correct answer: B — 2.5 amperes. From the official ISED question bank, verified word for word.
Why
To find the current, divide the power in watts by the voltage in volts. The full explanation — and one for every question — is in Pro.
Practise this section
Basic electronics and theory is section B-005 of the Basic exam: 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.
Drill B-005 — free, no account