PRECAUTION: Do not keep the switch on too long. It will heat the battery and cause it to run down. 1. RESULTS 1. Set the rheostat to any resistance 2. Take the reading on the voltmeter and ammeter. 3. 4. Repeat step two 5 times (or more) after changing the resistance provided by the rheostat each time. Tabulate the terminal potential difference (volts)- and electric current (amperes) readings obtained from the experiment. (10) INTERPRETATION AND DISCUSSION OF RESULTS 2. Identify the: 2.1 Independent variable 2.2 Dependent variable 2.3 Control variable 3. Why do we include a rheostat in the circuit? 4. Draw a graph of the voltmeter readings versus ammeter readings. 5. Is the gradient of the graph positive or negative? Explain. 6. Use the graph to determine the internal resistance of the battery. (3x2) (6) (2) (8) (3) (4) (4) 7. Which point on your graph represents the emf of the battery? Explain. CONCLUSION 8. Draw a conclusion from the results obtained. 23
