Skip to content
QuizQuip
Sign up
Back to Chapter 6
Mark schemePDF

Chapter 6 Practice Paper: Practical Electricity — question paper

QuizQuipPractice Series
QQ/S4CPH/CH6

Secondary 4 · Combined Science (Physics) (G2 / G3)

Chapter 6 Practice Paper

Practical Electricity

Duration: 40 minutes
Total: 30 marks
Name:
Class:
Register No.:
Date:

READ THESE INSTRUCTIONS FIRST

  • Answer all questions.
  • Section A: choose the one correct answer for each multiple-choice question.
  • Section B: answer in the spaces provided; show all necessary working.
  • Give numerical answers to 3 significant figures where appropriate, with units.
  • The acceleration of free fall near the Earth is 10 m/s².
  • The speed of sound in air is 340 m/s unless stated otherwise.
  • The use of a calculator is permitted.

Original practice material written for the MOE Combined Science (Physics) syllabus. It is not an official MOE or school examination paper. Chapter 6 (heating-effect appliances; P = VI; E = VIt; cost in kW h; hazards — damaged insulation, overheating cables, damp; fuses and circuit breakers with ratings; earthing and double insulation; live, neutral, earth and plug wiring).

For Examiner’s Use
Section A/ 10
Section B/ 20
Total/ 30

Section A: Multiple-choice questions[10 marks]

Choose the one correct answer for each question. Mains p.d. = 230 V.

  1. 1

    In which appliance does a current deliberately produce heat for its main job?

    1. Aelectric iron
    2. Belectric fan
    3. Cdoorbell
    4. Dcalculator
    ( )
  2. 2

    A 920 W heater runs from the 230 V mains. The current it draws is

    1. A0.25 A
    2. B2.0 A
    3. C4.0 A
    4. D5.0 A
    ( )
  3. 3

    The fuse chosen for an appliance should have a rating

    1. Afar above the normal current
    2. Bjust above the normal current
    3. Cbelow the normal current
    4. Dequal to the p.d.
    ( )
  4. 4

    The earth wire is included so that, if a live wire touches a metal case,

    1. Athe case stays at high potential harmlessly
    2. Bthe appliance keeps working normally
    3. Cthe current reverses
    4. Da large current flows to earth and blows the fuse
    ( )
  5. 5

    Switches and fuses are connected in the live wire so that, when they open,

    1. Athe appliance is completely disconnected from the high p.d.
    2. Bonly the neutral is disconnected
    3. Cthe earth wire carries the current
    4. Dthe circuit stays live
    ( )

Section B: Structured questions[20 marks]

Answer all questions in the spaces provided. Show all necessary working. Mains p.d. = 230 V; electricity costs 30 cents per kW h.

  1. 1

    An electric oven is rated 2000 W at 230 V and is used for 4.0 hours.

    1. (a)

      Calculate the current the oven draws.

      I =A[2]
    2. (b)

      Calculate the energy transferred in kW h during the 4.0 hours.

      E =kW h[2]
    3. (c)

      Calculate the cost of running the oven for these 4.0 hours.

      cost =[2]
  2. 2

    A metal-cased washing machine is connected by a correctly wired three-pin plug to the mains.

    1. (a)

      State the three wires in the plug, their colour codes, and where each connects.

      [3]
    2. (b)

      A broken wire inside the machine touches the metal case. Explain how the earth wire and the fuse together make the situation safe.

      [3]
    3. (c)

      State why a plastic-cased hairdryer needs no earth wire.

      [1]
  3. 3

    A convector heater draws 8.0 A at 230 V for 30 minutes.

    1. (a)

      Calculate the power of the heater.

      P =W[2]
    2. (b)

      Calculate the energy transferred in 30 minutes, in joules and in kW h.

      E =J[3]
    3. (c)

      Choose a suitable fuse rating from 3 A, 13 A and 30 A, and justify the choice.

      [2]

— End of paper —