1An immersion rod used for heating water has a resistance of 40 Ω. Calculate the current through it when it is connected to a 220 V socket.
2From the shape of the V and I graph drawn in Activity 11.3, what conclusion can be drawn?
3In Activity 11.4, what conclusion follows from working out the ratio of V to I in both cases?
4State Ohm's law and express it mathematically.
5What is electric resistance? Why does a conductor have resistance?
6What is meant by a resistance of 1 Ω?
7Show that the ohm is a derived unit.
8List the factors that affect the resistance of a conductor.
9A bulb carries 0.5 A when the potential difference across it is 6 V. What is its resistance?
10Why is copper used for house wiring but nichrome for heater coils?