Electric current is measured in amperes with an ammeter, so this Year 7 sheet begins with the instrument and the unit for current. Copper and an open circuit both appear in the key, and a switch is a later answer.
Key Takeaways
The unit of electric current is the ampere (Q1).
An ammeter measures electric current (Q2).
The key records copper and open circuit among the answers.
Section A: Multiple Choice Questions (1 Mark Each)
Choose the correct option for each question.
1.The unit of electric current is the...
(a) volt(b) ohm(c) ampere(d) watt
2.Which instrument is used to measure electric current?
3.Which of these materials is a good conductor of electricity?
(a) rubber(b) wood(c) copper(d) plastic
4.A circuit with a gap so that no current flows is called an...
(a) closed circuit(b) short circuit(c) open circuit(d) series circuit
5.The component used to control whether current flows in a circuit is a...
(a) switch(b) bulb(c) wire(d) cell
6.A battery converts...
(a) electrical energy into chemical energy(b) chemical energy into electrical energy(c) sound energy into light energy(d) heat energy into sound energy
Section B: Short Answer Type Questions (2 Marks Each)
Show all steps clearly.
7.Name two good conductors of electricity and two insulators.
8.What is an electric current?
9.State the unit of electric current and name the instrument used to measure it.
10.What is the difference between an open circuit and a closed circuit?
11.Describe how to connect a cell, a bulb, a switch and wires to make a circuit in which the bulb can be turned on and off.
12.Explain why copper is commonly used for electrical wires.
13.Two identical bulbs are added in series to a circuit that already has one bulb. What happens to the brightness of the bulbs and why?
14.State one safety rule that must be followed when using electricity.
Section C: Numericals & Word Problems (3 Marks Each)
Apply the concepts to solve the problems. Show all working.
15.A current of 2 A flows through a wire for 5 s. Use charge = current × time to calculate the charge that passes in coulombs.
16.A current of 3 A flows through a circuit for 10 s. Use charge = current × time to calculate the total charge in coulombs.
17.Two identical bulbs are connected in series and a current of 1 A flows through each bulb. What is the current in the main circuit?
18.Three identical bulbs are connected in series to a 6 V battery. The voltages across the bulbs add up to the battery voltage. Calculate the voltage across each bulb.
19.A charge of 20 C passes through a lamp in 4 s. Use current = charge ÷ time to calculate the current in amperes.
20.Two cells, each with a voltage of 1.5 V, are connected in series. Use total voltage = sum of the cell voltages to calculate the total voltage.
Answer Key
1. c) ampere
2. b) ammeter
3. c) copper
4. c) open circuit
5. a) switch
6. b) chemical energy into electrical energy
7. Refer to solution guide.
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End of Worksheet
People Also Ask
What is the unit of electric current?
The ampere, option (c) in this worksheet (Q1).
Which instrument measures electric current?
An ammeter, option (b) in this worksheet (Q2).
What material conducts electricity among the options?
Copper, from the answer key on this page.
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