Physics – 4.2.4 Resistance | e-Consult
4.2.4 Resistance (1 questions)
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Experiment: Determining Resistance using a Voltmeter and Ammeter
Apparatus:
- Resistor (known resistance, e.g., 100Ω)
- Voltmeter
- Ammeter
- Power supply (variable voltage)
- Connecting wires
- Circuit board or breadboard
Diagram:
[Image missing: Circuit Diagram]
Procedure:
- Construct the circuit as shown in the diagram. Ensure correct polarity of the voltmeter and ammeter.
- Connect the power supply.
- Set the power supply to a low voltage (e.g., 1V).
- Record the voltage (V) and current (I) readings from the voltmeter and ammeter, respectively. Repeat for several different voltage settings.
- Calculate the resistance (R) using Ohm's Law: R = V / I
- Plot a graph of Voltage (V) on the y-axis and Current (I) on the x-axis.
- The gradient of the graph will be equal to the resistance of the resistor.
Calculations:
The resistance (R) of the resistor can be calculated using Ohm's Law: R = V / I, where V is the voltage across the resistor and I is the current flowing through it. By taking readings at multiple voltage levels and plotting a graph of V vs I, the resistance can be determined from the gradient of the line.