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An experiment was set up to investigate the variation of the resistance R of a metallic conductor with its temperature θ - 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 θ. (i) Draw a labelled diagram of the apparat... 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 θ - Leaving Cert Physics - Question 4 - 2017
Step 1
Draw a labelled diagram of the apparatus used in this experiment.
Answer
To investigate the variation of resistance R with temperature θ, a simple circuit can be set up. The diagram should include:
- An ohmmeter or multimeter for measuring resistance.
- A power source (like a battery).
- A metallic conductor (the sample whose resistance is being tested).
- Connecting wires with proper insulation.
- A heat source (like a Bunsen burner or water bath).
- A thermometer to monitor temperature. All components must be clearly labelled, including the direction of current flow.
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 device would be set to read ohms, and the metallic conductor was connected in the circuit. The value displayed on the device represented the resistance R at each corresponding temperature θ, providing precise readings for analysis.
Step 3
Using the data in the table, draw a graph on graph paper, to show the variation of resistance of the metallic conductor with temperature.
Answer
The graph should be plotted with θ (temperature in °C) on the x-axis and R (resistance in Ω) on the y-axis. Points are plotted as follows:
- (0, 19.6)
- (15, 20.6)
- (30, 21.6)
- (40, 22.1)
- (60, 23.5)
- (80, 24.8)
- (100, 26.1) Once points are plotted, a straight line should be drawn to connect them, indicating the trend of resistance changing with temperature.
Step 4
What does the graph tell you about the relationship between the resistance of a metallic conductor and its temperature?
Answer
The graph shows a positive correlation between the resistance of the metallic conductor and its temperature. As the temperature increases, the resistance also increases. This relationship is typical for metallic conductors, as higher temperatures result in increased atomic vibrations, which impede the flow of electrons, thereby increasing resistance.
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 at which the resistance is 22.8 Ω, locate 22.8 Ω on the y-axis of the graph. From that point, draw a horizontal line until it intersects the plotted line. Then, drop a vertical line down to the x-axis to find the corresponding temperature. From the graph, we estimate this temperature to be approximately 47 °C.