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In an experiment to investigate the variation of resistance with temperature for a metallic conductor in the form of a wire, a student measured the resistance of the conductor at different temperatures - Leaving Cert Physics - Question 4 - 2006
Question 4
In an experiment to investigate the variation of resistance with temperature for a metallic conductor in the form of a wire, a student measured the resistance of the... show full transcript
Worked Solution & Example Answer:In an experiment to investigate the variation of resistance with temperature for a metallic conductor in the form of a wire, a student measured the resistance of the conductor at different temperatures - Leaving Cert Physics - Question 4 - 2006
Step 1
How did the student measure the resistance of the wire?
Answer
The student measured the resistance of the wire using a multimeter or an ohmmeter. This involves connecting the device's probes to either end of the wire and reading the resistance directly on the display. The multimeter can be set to the resistance mode, ensuring that the circuit is not powered during the measurement to avoid damage and inaccurate readings.
Step 2
Describe, with the aid of a diagram, how the student varied the temperature of the wire.
Answer
To vary the temperature of the wire, the student could use a water bath as a heating source. The wire would be immersed in water, which is heated to raise its temperature. A thermometer would be placed in the water to monitor the precise temperature. The diagram should illustrate the setup, showing the water bath, wire submerged in it, the heat source, and the thermometer.
Step 3
Using the data in the table, draw a graph on graph paper of the resistance of the conductor against its temperature.
Answer
The graph should have temperature (°C) on the x-axis and resistance (Ω) on the y-axis. Each data point should be plotted accurately using the values from the table. For example, point (20, 45.6), (30, 49.2), ..., (70, 68.4). Once plotted, the points should be connected with a straight line to indicate the trend. The graph should also label the axes and provide units.
Step 4
Use the graph to estimate the temperature of the conductor when its resistance is 50 Ω.
Answer
To estimate the temperature corresponding to a resistance of 50 Ω, locate 50 Ω on the y-axis of the graph, then draw a horizontal line to intersect the plotted points. From the intersection, draw a vertical line to the x-axis to read the corresponding temperature. According to the graph, this temperature is estimated to be approximately 30 °C.
Step 5
What does your graph tell you about the relationship between the resistance of a metallic conductor and its temperature?
Answer
The graph indicates a positive correlation between the resistance of a metallic conductor and its temperature. As the temperature increases, the resistance also tends to increase. This relationship can be attributed to enhanced atomic vibrations within the conductor, which hinders the flow of electrons, resulting in higher resistance.