Electrical Science

Sample questions

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These sample questions are practice material and have not yet been reviewed by a qualified electrician. They are for revision only — working to BS 7671 on site is never decided by a quiz.

1. Q1.A 230 V supply feeds a heating element with a resistance of 23 Ω. What current flows?

   • 1 A
   • 10 A
   • 23 A
   • 100 A

2. Q2.Two 10 Ω resistors are connected in series. What is the total resistance?

   • 5 Ω
   • 10 Ω
   • 20 Ω
   • 100 Ω

3. Q3.Electrical power is measured in which unit?

   • Volts
   • Amperes
   • Watts
   • Ohms

4. Q4.The same two 10 Ω resistors are now connected in parallel. What is the total resistance?

   • 5 Ω
   • 10 Ω
   • 20 Ω
   • 40 Ω

5. Q5.A lamp draws 2 A from a 230 V supply. What power does it use?

   • 115 W
   • 230 W
   • 460 W
   • 1,150 W