Test items and tasks Electricity end-of-unit assessment
Objective items
1.
A torch battery is connected to a torch globe by two wires. The globe is glowing and giving out light.
Which is the best explanation for what happens to the electric current in the wires?
a. The electricity flows through wire A from the battery to the globe, which uses up all the electricity. Wire B is not needed.
b. The electric current flows through both wires to the globe where it is used up.
c. The electric current flows through one wire to the globe where some of it is used up. The remaining electric current flows through the other wire back to the battery.
d. The electric current flows round the circuit and none is used up by the globe, so that the amount of current in the two wires is the same.
2. Which of the following lists include only conductors of electricity?
a. iron, wood and paper
b. nichrome, plastic and paper
c. mercury, copper and carbon
d. wood, plastic and paper.
3. Use the words from here (torch, battery, connecting wire, variable resistor, switch, globe) to label the diagram below.
A is ______B is ______
C is ______D is ______
Is the globe working and lit up? ______
Explain your answer.
4. In a house there are four lights connected into a circuit as shown in this diagram.
a. Where would you put a switch that would turn all the lights off?
- A
- B
- C
- D.
b. Where would you put a switch that would turn one light off and leave three lights on?
- A
- B
- C
- D.
5. In which of the following circuits will the globe(s) be brightest?
A circuit containing:
a. one 2 V globe and one 1.5 V battery
b. two 2 V globes and one 1.5 V battery
c. two 2 V globes and two 1.5 V batteries
d. one 2 V globe and two 1.5 V batteries.
6. Which of the following wires is likely to have the greatest resistance?
a. A copper wire 0.2 mm thick and 10 cm long
b. A Nichrome wire 0.2 mm thick and 10 cm long
c. A Nichrome wire 0.1 mm thick and 15 cm long
d. A copper wire 0.3 mm thick and 5 cm long.
7. Which of the following electrical appliances will use the greatest amount of electrical energy?
An appliance with a rating of:
a. 1,000 watts used for 3 hours
b. 1,500 watts used for 3 hours
c. 800 watts used for 4 hours
d. 500 watts used for 5 hours.
Extended response items
8. Four electrical circuits were constructed including a torch globe, a battery and either a glass marble, an iron nail, a piece of aluminium foil or a pencil lead.
a. Which of the globes will light up?
b. Why would these globes light up?
c. Why would the other globe(s) not light up?
9. Some materials are conductors of electricity while others are insulators.
a. What are conductors used for? Explain using an example.
b. What are insulators used for? Explain using an example.
c. What property of a material determines whether it will allow electricity to flow though it?
10. How is the amount of electricity flowing through a circuit affected by the number of batteries in the circuit?
11. How is the amount of electricity flowing through a circuit affected by the number of globes in the circuit?
12. What is voltage and how does it affect the amount of current flowing through a circuit?
13. What is resistance and how does it affect the amount of current flowing through a circuit?
14. The Kelly family live in Alice Springs, which is hot in summer and cold in winter. Mr and Mrs Kelly both work full time in normal office hours, five days per week. Children Matthew, George and Katy all attend the local high school. The Kellys have an electrical hot water system that heats water as it is used, they use electricity for cooking and for air-conditioning, and they have a gas room heater in the living area of their home. Consider the patterns of electricity consumption in the Kellys’ home.
a. Explain how electricity consumption will vary:
i. during a single working day ie Monday to Friday
ii. between week days and weekend days
iii. between summer and winter.
b. What suggestions would you make to reduce the Kellys’ consumption of gas and electricity?
ã Commonwealth of Australia, 2003 2