10.1 A learner sets up the circuit below to investigate the relationship between current and potential difference across the ends of a conductor. She closes the switch and records the ammeter and voltmeter readings. She repeats the experiment three times; each time she increases the number of cells in the circuit. Then she reads and records the ammeter and voltmeter readings.
A graph of her results is shown below.
10.1.1 Which physical quantity does the gradient of the graph represent? (1)
10.1.2 Use the information from the graph to calculate the resistance of the
resistor that the learner used in the investigation. (3)
10.2 The battery in the circuit diagram below has negligible internal resistance. The
resistance of resistor R is unknown. When the switch is closed, the voltmeter
reads 15 V and the ammeter A 1 reads 1 A.
Calculate the:
10.2.1 Current in ammeter A (3)
10.2.2 Resistance of resistor R (5)
10.3 The resistor R of unknown resistance is now removed from the circuit. How
will this change in the circuit affect the reading of the ammeter A?
Answer INCREASE, DECREASE or REMAIN THE SAME. Explain your
answer. (2)
10.4 The power rating on an electric stove is 1 500 W. If the stove is used for
3 hours and 30 minutes, calculate how much it will cost to use the stove.
1 unit of electricity (1 kWh of electricity) costs R1,15. (3)
[17]
TOTAL: 150