Ohm's Law
Aim:To prove ohms' law, and to study the relationship between current
and potential difference (voltage).
Hypothesis: The current flowing through a metal wire is proportional
to the potential difference across it (providing the temperature is
constant).
Apparatus:
1. Power Supply
2. Variable resistor
3. Ammeter
4. Voltmeter
5. Resistors
6. Electric wires
Diagrams:
=========
R1: R2:
R1 + R2 (in series): R1 + R2 (in parallel):
Method:
1. Set up the apparatus 4 times as shown in the diagrams above
2. Set the power supply to 6v
3. Set the variable resistor to maximum resistance
4. Switch on the power and note the ammeter and voltmeter readings
5. Reduce the resistance of the variable resistor
6. Repeat steps 4, and 5 until at least five 8 sets of readings have
been obtained
7. Change the setting of the apparatus as shown in the diagrams
above, and perform steps 2 - 6 with each setting of apparatus
Results:
· Table of results for one resistor of 12Ω
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Current (A)
Voltage (v)
0.18
2.18
0.20
2.30
0.22
2.52
0.24
2.79
0.26
3.02
0.28
3.39
0.30
3.62
0.38
4.41
· Table of results for one resistor of 10Ω
Current (A)
Voltage (v)
0.18
1.80
0.20
2.06
0.22
2.23
0.24
2.46
0.26
2.67
0.28
2.95
0.30
3.19
0.39
3.99
· Table of results for two resistors in series of 10Ω + 12 Ω = 22Ω
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