___________ ___________ is the flow of electric charge. ___________ is the opposition to flow of electrons in a circuit. Complete the table below:
Symbol Current
Potential difference Resistance
16. 17. 18. 19. 20.
K U V Ohmmeter
The symbol for a switch is ___________. The symbol for a lamp is ___________. A battery is represented by the symbol ___________. State Ohm’s Law. _________________________________________________________. Electrical power is the rate at which ___________ ___________ is either produced or ___________.
1. 2.
3. 4. 5.
6. 7.
8. 9.
10. 11.
12. 13.
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Knowledge and Understanding Explain how objects can become charged.
What happens when two things with the same type of charge are brought into close contact? Describe an experiment you could carry out to determine if an object is a conductor or an insulator. Electricians often use an instrument called a multimeter. What do you think a multimeter can be used for? When one bulb stops working on your Christmas tree lights, they may all stop working. Why do you think this is? Describe the relationship between potential difference and current in an electric circuit. If a voltage of 8 volts gives a current of 2 amps across a resistor, what is the resistance of the resistor? What current will a circuit with a voltage of 6 volts give if it contains a 3 ohm resistor? What voltage would need to be applied to a circuit with 6 ohms of resistance and 2 amps of current? Draw a diagram of the apparatus you would use to verify Ohm’s Law. The picture shows a CFL light bulb. (a) What does the power label tell us? (b) Why is it considered environmentally friendly to use this type of light bulb? Draw a circuit diagram for a circuit containing two light bulbs in parallel, a battery and a switch. In the circuit you drew for question 12, if one light bulb blows what happens to the other light bulb? Why?
Unit Amperes (amps) Unit symbol A Measuring instrument
