Electrical theory / Preview

Work through the numbers. Understand each step.

Practise basic electrical theory, then choose the right Hong Kong exam route. Start with five original questions and a calculation tool.

Try the five questions →

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01 / THEORY LAB

Ohm’s law & energy calculator

Change the values to see current, power and energy for an ideal DC resistive load.

Three-phase power calculator and worked examples →

02 / FIVE ORIGINAL QUESTIONS

Try five questions. Read every reason.

0 / 5

1. A resistor has 12 V across it and carries 2 A. What is its resistance?6 Ω24 Ω10 Ω

2. A 230 V ideal resistive load draws 4 A. What is its power?57.5 W920 W234 W

3. A 0.8 kW load runs for 2.5 hours. How much energy is used?3.3 kWh0.32 kWh2 kWh

4. Two resistors of 5 Ω and 7 Ω are in series. Find total resistance.12 Ω35 Ω2 Ω

5. Two equal 10 Ω resistors are in parallel. Find total resistance.20 Ω5 Ω10 Ω

03 / HONG KONG EXAM ROUTES

Choose the correct route before you revise

Grade A: CIC trade test

Prepare both written knowledge and the practical trade test. Passing a test alone does not confer electrical-worker registration; check the EMSD eligibility conditions.

CIC Grade A information ↗

Grade B: HKEAA registration examination

Grade B follows a different examination and eligibility route. Use the HKEAA syllabus and examination arrangements rather than treating Grade A practice as a complete Grade B mock.

HKEAA Grade B information ↗

Official routes checked 1 October 2026. This pilot contains five theory questions; the linked iOS app currently publishes Grade A content. Grade B full mocks are not available here.

Continue Grade A practice in the app ↗