Form 3 Chapter 8

CHAPTER 8 GENERATION OF ELECTRICITY

1. Diagram 1 shows a simple transformer which is made of two coils of wire wrapped around an iron core.

S R

P: ………………………………

Q: ………………………………

Diagram 1 (a) What type of transformer is this? …………………………………………………………………………………………………….. [1 mark]

(b) What is the use of this transformer? ……………………………………………………………………………………………….......... [1 mark] (c) Label coil P and coil Q on Diagram 1. [2 marks] (d) Compare the brightness of bulb R and bulb S. ……………………………………………………………………………………………………… [1 mark]

(e) What will happen to the brightness of bulb R and bulb S if coil P and coil R are reversed? ………………………………………………………………………………………………..........

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[1 mark] 2. Diagram 2 shows the structure of a 3-pin plug Q: ………………………..

S P: ……………………….. R: ………………………..

Diagram 2

(a) On Diagram 2, label structure P, Q and R using the following words. Live wire

Earth wire

Neutral wire [3 marks]

(b) Draw line to show the correct match between the wires and their functions Wire

Function

P

Carry electric current back to the mains

Q

Carry leaked current to the Earth

R

Carry electric current to the electrical appliance [3 marks]

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(c) Draw line to show the correct match between the wires and their colours. Wire

Colour Blue

P

Q

Brown

R

Yellow with green stripes [3 marks]

(d) (i) Name the component labelled S. …………………………………………………………………………………………………… [1 mark] (ii) State the function of the component labelled S ………………………………………………………………………………………………….. [1 mark]

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3. Diagram 3 shows two commercial methods of generating electricity commonly used in Malaysia. P

Q

Diagram 3 (a) Name the type of electric generator shown in Diagram 3. P :.....……………………………………………………………………………………………….. Q: ……….………………………………………………………………………………………….. [2 marks]

(b) State the energy change that takes place in Q. …………………………………………………………………………………………………….. [1 mark]

(c) State one disadvantage of using P to generate electricity. ……………………………………………………………………………………………………… [1 mark] (d) State one advantage of using Q to generate electricity. ……………………………………………………………………………………………………… [1 mark] (e) Apart from P and Q, name another type of electrical generator used in Malaysia. ………………………………………………………………………………………………………

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[1 mark]

4. Diagram 4.1 shows the electrical wiring system in the house. Q: ……………………………..

P: …………………………

R: ……………………… Diagram 4.1

(a) On Diagram 4.1, label P, Q and R with the following words. Fuse box

Main fuse

Electric meter [3 marks]

(b) What is the function of (i)

P? ………………………………………………………………………………………… ……

(ii)

Q? ………………………………………………………………………………………… ….. [2 marks]

(c) Why are the lights in the lighting circuit connected in parallel? ……………………………………………………………………………………………………… [1 mark]

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(d) Diagram 4.2 shows the readings of an electric meter for a household. Previous Reading

0

2

4

6

5

Current Reading

5

0

2

4

9

kWh

3

8 kWh

DIAGRAM 4.2 (i)

Calculate the number of electrical energy units used by the household.

[2 marks] (ii)

Table 4.3 shows the rate of electrical energy charged by the electrical power supplier. Charge First Consecutive

Unit 200 500

Rate RM 0.32 RM 0.38

Table 4.3 Calculate the cost of electrical energy used by the household in (d)(i).

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[2 marks] 5. Diagram 5 shows the electrical energy transmission and distribution system.

P: ……………………………..

Q: ……………………………..

M

N

R: ……………………………

Diagram 5 (a) Label P, Q and R on Diagram 5 using the following words. Switch zone

Power station

Main substation [3 marks]

(b) What is the function of Q? ……………………………………………………………………………………………………… [1 mark] (c) What is the difference between M and N? ……………………………………………………………………………………………………… [1 mark]

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(d) State one advantage of the National Grid Network. ……………………………………………………………………………………………………… [1 mark]

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