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An experiment was set up to investigate the variation of the resistance R of a metallic conductor with its temperature \( \theta \) - Leaving Cert Physics - Question 4 - 2017
Question 4
An experiment was set up to investigate the variation of the resistance R of a metallic conductor with its temperature \( \theta \). (i) Draw a labelled diagram of ... show full transcript
Worked Solution & Example Answer:An experiment was set up to investigate the variation of the resistance R of a metallic conductor with its temperature \( \theta \) - Leaving Cert Physics - Question 4 - 2017
Step 1
Draw a labelled diagram of the apparatus used in this experiment.
Answer
To draw the apparatus, include the following elements:
- Power Supply: Indicate the power source used for the experiment, such as a battery.
- Ohmmeter/Multimeter: A device to measure the resistance, with clear labels showing the positive and negative terminals.
- Metallic Conductor: Depict the wire or metallic piece whose resistance is being measured.
- Thermometer: Show a thermometer in contact with the conductor to measure temperature.
- Connecting Wires: Draw wires connecting the components, with arrows indicating the direction of current flow. Include insulation on the wires for clarity.
Step 2
How was the value of the resistance of the metallic conductor measured?
Answer
The resistance of the metallic conductor was measured using an ohmmeter or multimeter. The multimeter is set to the resistance measurement mode, and the probes are connected across the conductor. The measured value displayed on the multimeter indicates the resistance in ohms. It is important to ensure that the conductor is at a constant temperature during the measurement.
Step 3
Using the data in the table, draw a graph, on graph paper, to show the variation of the resistance of the metallic conductor with temperature.
Answer
To create the graph:
- Label the Axes: The x-axis represents temperature (°C) while the y-axis represents resistance (Ω).
- Plot Data Points: Mark the points from the table, corresponding to temperatures and their respective resistances.
- Connect Points: Draw a straight line or curve through the points to illustrate the relationship. Make sure to extend the line to indicate the trend.
Step 4
What does the graph tell you about the relationship between the resistance of a metallic conductor and its temperature?
Answer
The graph indicates a direct relationship between the resistance of the metallic conductor and its temperature. As the temperature increases, the resistance also increases. This behavior is typical for metallic conductors due to increased thermal vibrations of the atoms, which impede the flow of electrons.
Step 5
Use your graph to find the temperature of the metallic conductor when it has a resistance of 22.8 Ω.
Answer
To find the temperature corresponding to a resistance of 22.8 Ω, locate this value on the y-axis of the graph, then draw a horizontal line until it intersects with the plotted line. From the intersection point, draw a vertical line down to the x-axis to find the temperature. The temperature should be approximately 47°C.