7/31/2019 Exercise on Chapter 8 Science Form 3

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EXERCISE ON CHAPTER 8 SCIENCE FORM 3

1. Which generator uses water to operate?A. Diesel generatorB. Thermal generatorC. Gas turbine generatorD.

Hydroelectric generator

2. Which of the following is true about gas turbine generators?A. It does not need a dynamoB. It does not need fuel to operateC. It changes potential energy to electrical energyD. Its operation is based on the compression of gas and air.

3. What is the voltage of electricity generated at the power station?A. 240 V C. 11000 VB. 415 V D. 66000 V

4. A certain electrical appliance has a power of 200W. This means that the appliance uses A. 200 J of electrical energy every secondB. 200 kJ of electrical energy every secondC. 200 W of electrical energy every secondD. 200 kW of electrical energy every second

5. How much electrical energy does a 150 W refrigerator use in one day?A. 0.36 kWhB. 36 kWhC. 3.6 kWhD. 360 kWh

6. If a 100 W lamp is used for 16 hours a day, the cost of using it for 40 days at 25 cents per kWh isA. RM 1.60B. RM 10C. RM 16D. RM 160

7. Why is electrical energy usually transmitted at a high voltage?A. The transmission cables waste as little energy as possibleB. The transmission cables are safe to handleC. The transmission system does not require a transformerD. The transmission system does not require a switch board

8. A mains switch is connected to which of the following?A. Earth wireB. Neutral wireC. Live wire from the mains supplyD. Lightning conductor

9. When in use, the metal casings of electrical appliances are connected to earth in order to A. make the casings liveB. make the fuse workC. make the voltage of the casings zeroD. reduce resistance

10.Which of the following sources of energy are used to generate electricity?I. Diesel oil

II. PetroleumIII. Radioactive substances

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A. I and II only C. II and III onlyB. I and III only D. I,II and III

11.Which are the alternative sources of energy that can generate electrical energy that can generate electricalenergy?

I. Solar energyII. Wave energy

III. Biomass energyA. I and II only C. II and III onlyB. I and III only D. I,II and III

12.Which of the following generators is not correct about how the turbine is rotated?

13.Diagram 1 shows two transformers. Identical bulbs M1, M2 and M3 are connected as shown in diagram 1.The voltage across M1 is the same in each circuit.

Which is true about the brightness of bulbs M1, M2and M3 ?

M1 M2 M3

A. Brighter thanM2

Less brighter

than M3Brighter than M1

B. Less brighterthan M3

Brighter than

M1Brighter than M2

C. Brighter thanM2

Less brighterthan M3

Less brighter thanM1

D. Less brighterthan M3

Brighter than

M1Less brighter than

M2

14.Touching switches and operating electrical appliances with wet hands can cause an electric shock because.A. a short circuit may occur.B. electricity will flow to the earth connection.C. electricity flows more easily through wet things.D. this will increase the amount of current in the circuit.

15.A 2kW electric kettle is used for 0.5 hour. What is the cost of using it if TNB charges 20 cent for every kWh?A. 40 centB. 20 centC. 80 centD. 50 cent

16.The alternating current supplied to our house is not suitable for. A. an electric kettleB. an electric ironC. charging a batteryD. decorative lights

17.If the cost of I kWh of electricity is RM 0.25, what is the cost of using a 2 kW air conditioner for 8 hours?

Generator Turbine rotated byA. Gas turbine Hydrogen

B. Diesel Engine

C. Hydro WaterD. Thermal Steam

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A. RM 2.40B. RM3.60C. RM4.00D. RM4.80

18.An appliance that uses 2.5 A of current should be fitted with a fuse ofA. 1 AB. 2.5 AC. 3 AD. 10 A

19.What is the use of the earth wire in the domestic wiring system?A. To replace fusses if ant short circuit occursB. To provide a low-resistance connection to the earthC. To keep the voltage of all appliances the same as that of the neutral wireD. To provide a way to conduct the current to earth when overloading occurs

20.Which of the following is not a safety device in the wiring system at home?A. FuseB. Earth wireC. Circuit breakerD. A 3-pin plug