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Science questions, unit 7
Nama / NameKelas / ClassTarikh / Date

Electricity

27 marks. Use Practice to check each answer as you go, or Exam to answer everything first. Ask a grown-up to help you mark the written answers.

Section A: objective questions

10 marks
Choose the best answer for each question.
1

Question 1

What is the function of a bulb?
Show answerHide answer
B
A bulb produces light.
For the teacher: Remembering, low difficulty, standard 7.1.2
Textbook p. 76
2

Question 2

What is the function of a switch?
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D
A switch completes the circuit when it is closed and breaks it when it is opened.
For the teacher: Remembering, low difficulty, standard 7.1.2
Textbook p. 76
3

Question 3

Diagram 1 shows a circuit. The switch is closed. What happens to the bulb?
A circuit with a dry cell, a switch and a bulb that is lit
Diagram 1
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A
The circuit is complete, so the bulb lights up.
For the teacher: Understanding, low difficulty, standard 7.1.3
Textbook p. 75
4

Question 4

Diagram 2 shows three circuits. Which bulb lights up?
Circuit A has an opened switch. Circuit B has no dry cell. Circuit C is complete.
Diagram 2
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C
Only circuit C is complete. Circuit A has an opened switch and circuit B has no dry cell.
For the teacher: Understanding, low difficulty, standard 7.1.3
Textbook p. 86
5

Question 5

The switch is opened and the bulb does not light up. What kind of circuit is this?
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B
An opened switch leaves a gap, so the circuit is incomplete.
For the teacher: Understanding, low difficulty, standard 7.1.3
Textbook p. 85
6

Question 6

The switch is closed, but the bulb does not light up. Which can be the reason?
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C
A dry cell with no energy cannot make the bulb light up.
For the teacher: Applying, medium difficulty, standard 7.1.4
Textbook p. 79
7

Question 7

Which object is a conductor?
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A
A paper clip is metal. It lets electric current flow through it.
For the teacher: Remembering, low difficulty, standard 7.1.5
Textbook p. 85
8

Question 8

Which object is an insulator?
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D
Rubber does not let electric current flow through it.
For the teacher: Remembering, low difficulty, standard 7.1.6
Textbook p. 85
9

Question 9

Ravi puts an ice cream stick in place of the switch. The bulb does not light up. What is the ice cream stick?
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C
The bulb stays dark, so the stick does not let electric current flow. It is an insulator.
For the teacher: Applying, medium difficulty, standard 7.1.7
Textbook p. 82
10

Question 10

What do we use to join the electrical components into a circuit?
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A
Connecting wires join every component into a complete circuit.
For the teacher: Remembering, low difficulty, standard 7.1.1
Textbook p. 75

Section B: structured questions

17 marks
Answer all questions. Write your answers in the spaces provided.
11

Question 11

Diagram 3 shows three electrical components. Which component does each job?
A dry cell, a bulb and a switch
Diagram 3
[1 mark] (a)Supplies electrical energy
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Dry cell
[1 mark] (b)Produces light
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Bulb
[1 mark] (c)Completes and breaks the circuit
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Switch
For the teacher: Remembering, low difficulty, standard 7.1.2
Textbook p. 76
12

Question 12

Look at Diagram 2 again. Only one bulb lights up.
Circuit A has an opened switch. Circuit B has no dry cell. Circuit C is complete.
Diagram 2
[1 mark] (a)Why does the bulb in circuit C light up?
Show answerHide answer
Textbook answer (p. 130, I Answer p. 85).
Tick each point you got.
[1 mark] (b)Why does the bulb in circuit A not light up?
Show answerHide answer
Tick each point you got.
[1 mark] (c)Why does the bulb in circuit B not light up?
Show answerHide answer
Tick each point you got.
For the teacher: Understanding, medium difficulty, standard 7.1.3
Textbook p. 86
13

Question 13

Choose the correct word.
[1 mark] (a)The bulb lights up when the switch is ______.
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closed
[1 mark] (b)The bulb does not light up when the switch is ______.
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opened
For the teacher: Applying, low difficulty, standard 7.1.3
Textbook p. 78
14

Question 14

Diagram 4 shows six objects: a banknote, a fork, a leaf, a nail, a reel of thread and a screw.
A banknote, a fork, a leaf, a nail, a reel of thread and a screw
Diagram 4
[2 marks] (a)Write two objects that are conductors.
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Textbook answer (p. 85, I Answer): the fork, nail and screw are conductors.
Tick each point you got.
[2 marks] (b)Write two objects that are insulators.
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Tick each point you got.
For the teacher: Applying, medium difficulty, standard 7.1.7
Textbook p. 86
15

Question 15

Are these sentences true or false?
[1 mark] (a)A conductor lets electric current flow through it.
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True
[1 mark] (b)An insulator lets electric current flow through it.
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False
For the teacher: Understanding, low difficulty, standard 7.1.5
Textbook p. 83
16

Question 16

Kugan's circuit is complete, but his bulb does not light up. He changes the bulb and the dry cell. It still does not light up.
[1 mark] (a)Give one other reason why the bulb does not light up.
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Textbook answer (p. 130, HOTS p. 80): faulty bulb holder, wire, dry cell holder or switch; also p. 81: bulb not fastened properly or wire not connected.
Tick each point you got.
For the teacher: Analysing, medium difficulty, standard 7.1.4
Textbook p. 80
17

Question 17

A circuit is left complete for one whole day.
[1 mark] (a)What happens to the brightness of the bulb?
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Tick each point you got.
[1 mark] (b)Why?
Show answerHide answer
Textbook answer (HOTS p. 78).
Tick each point you got.
For the teacher: Evaluating, high difficulty, standard 7.1.3
Textbook p. 78