Grade 9: Electricity Revision 2

1.

Multiple Choice

30 sec

1 pt

The following statements about a circuit overload are true except ______:

Too much current can cause overheating and possibly a fire

The current in the circuit is linked to the power rating of the appliance

Too many appliances on one circuit will overload the circuit

Overloading happens when 1 or 2 appliances are being used at a time.

2.

Multiple Choice

30 sec

1 pt

Choose the correct phrase to complete the following sentence: Earthing is_________

Current running through an unintended path

Instantaneous discharge directly to the earth

A thin wire that will melt and break the circuit when overloaded

A flow of electrons through the neutral wire

3.

Multiple Choice

30 sec

1 pt

The purpose of a 3-point plug is to:

Draw a greater current to operate appliances.

Make it easier to plug in.

It has an earth wire as a safety protector

Provide a closed circuit by connecting the live and neutral wires

4.

Multiple Choice

30 sec

1 pt

A thin wire that will melt and break the circuit when overloaded is called a:

Trip switch

Fuse

Earth leakage

rheostat

5.

Multiple Choice

30 sec

1 pt

In a three point plug _____

The green and yellow wire complete the circuit for the flow of current

The blue and brown wires need to be connected to each other in order to conduct the current

The green and yellow wire connects to the metal casing of an appliance for safety

The blue wire is live and the brown is neutral

6.

Multiple Choice

30 sec

1 pt

An example of a renewable energy source is

Uranium

Wind

Coal

Natural Gas

7.

Multiple Choice

30 sec

1 pt

An example of a non-renewable energy resource is:

Wind

Crude oil

Waves

The sun

8.

Multiple Choice

30 sec

1 pt

The following are all examples of fossil fuels, except:

Crude oil

Uranium

Natural Gas

Coal

9.

Multiple Choice

30 sec

1 pt

Hydroelectric power can be provided by all of the following except:

A thunderstorm

Waves

Dams

Falling water

10.

Multiple Choice

30 sec

1 pt

Two hydrogen atoms merging to form a helium atom and large amounts of energy is an example of:

A non-renewable power sorce

Nuclear fission

Nuclear fusion

Hydrogen power

11.

Multiple Choice

30 sec

1 pt

The unit for the consumption of electrical energy in a household is:

Watt/second

kWh

Joule

Watt

12.

Multiple Choice

1 min

2 pts

A bulb has a power rating of 60W. The electricity consumed by the bulb in 6 hours will be:

36 Units

3,6 Units

0.36 Units

360 Units

13.

Multiple Choice

1 min

3 pts

A kettle with a power rating of 2 500 W is used to boil water for 3 minutes. How many units of electrical energy are consumed each time the kettle is boiled?

0.75kWh

0,125kWh

7,5 kWh

12,5kWh

14.

Multiple Choice

2 mins

3 pts

Thato lives in an apartment that has a hot water geyser that has a power rating of

1500W. To save electricity she switches it off for 5 hours a day. How much money will she save on her electricity account each time she does this if electricity is charged at 250c per unit?

R1,87

R7.50

1875c

187,5c

15.

Multiple Choice

30 sec

1 pt

A coal power station operates as follows

Coal → furnace → steam → turbine → generator

Coal → Steam → generator → turbine → furnace

Furnace → coal → crusher → turbine → generator

Neutrons bombard uranium nucleus → turbine → generator

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