Free mock exam
Power Factor — Level 3 Electrical Science Practice
Free topic-focused mock exam: 30 random questions from a pool of 44 on Power Factor, drawn from the wider Level 3 Electrical Science bank. 35-minute timer, 70% to pass, worked explanation on every question. Use this when you've taken the full mock once and want to drill the topics you got wrong.
- Questions
- 30
- Time limit
- 35 min
- Pass mark
- 70% · 21/30
- Question bank
- 44
Free, no sign-up. Retake as many times as you like — different questions each time.
Sample questions
01What does the power factor of an a.c. circuit express?
- AThe ratio of apparent power to true power (S/P)
- BThe ratio of reactive power to true power (Q/P)
- CThe ratio of reactive power to apparent power (sin φ)
- DThe ratio of true power to apparent power (cos φ)
Why: Power factor is the ratio of true power (W) to apparent power (VA): PF = P/S = cos φ. It indicates how effectively power is used.
02What is the ideal power factor?
- A0.5 (lagging)
- B0 (purely reactive)
- C1.0 (unity)
- D-1.0 (negative unity)
Why: Unity power factor (1.0) is ideal - all power supplied does useful work. Current and voltage are in phase.
03What type of load causes lagging power factor?
- AInductive
- BLED lights
- CCapacitive
- DResistive
Why: Inductive loads (motors, transformers, inductors) cause lagging power factor because current lags behind voltage.
Common questions
Is the Power Factor mock exam free?
Yes — 100% free, no sign-up needed. Questions are pulled at random from a substantial bank, with a worked explanation on every question after you submit.
Can I retake the mock exam?
Yes. Every attempt picks a different random selection and reshuffles the options, so each retake gives you genuinely new questions. No limit on retakes.
Does this count towards the real qualification?
No — this is independent practice material. To gain the actual qualification you need to sit the official assessment through an approved provider.
