Photo AI
In an experiment to investigate the variation of the resistance R of a thermistor with its temperature θ, a student measured the resistance of the thermistor at different temperatures - Leaving Cert Physics - Question 4 - 2009
Question 4
In an experiment to investigate the variation of the resistance R of a thermistor with its temperature θ, a student measured the resistance of the thermistor at diff... show full transcript
Worked Solution & Example Answer:In an experiment to investigate the variation of the resistance R of a thermistor with its temperature θ, a student measured the resistance of the thermistor at different temperatures - Leaving Cert Physics - Question 4 - 2009
Step 1
Draw a labelled diagram of the apparatus used in this experiment.
Answer
To draw the labelled diagram of the apparatus, include the following components:
- Thermistor in a water bath to maintain a consistent temperature.
- Oven or heat source for temperature control.
- Digital multimeter (ohmmeter) to measure resistance.
- Thermometer for monitoring temperature.
- Connecting wires between the components.
Ensure all components are clearly labelled and positioned appropriately.
Step 2
How did the student measure the resistance of the thermistor?
Answer
The student used a digital multimeter to measure the resistance of the thermistor. The multimeter was set to the resistance measurement mode. The thermistor was connected to the multimeter probes, allowing the student to read the resistance value directly on the display. Additionally, they ensured proper connections and calibration for accurate readings.
Step 3
Plot a graph on graph paper to show the relationship between resistance R and its temperature θ (put θ on the X-axis).
Answer
To plot the graph:
- Create a graph with the X-axis representing temperature (θ in °C) ranging from 20 to 80 °C.
- Set the Y-axis for resistance (R in Ω) ranging from 40 Ω to 2000 Ω.
- Mark the data points based on the given values:
- (20, 2000)
- (30, 1300)
- (40, 800)
- (50, 400)
- (60, 200)
- (70, 90)
- (80, 40)
- Connect the points with a smooth curve to illustrate the trend showing how resistance decreases as temperature increases.
Step 4
Use your graph to estimate the temperature of the thermistor when its resistance is 1000 Ω.
Answer
From the graph, find the point where the resistance value intersects with 1000 Ω. By tracing horizontally from this point to find the corresponding value on the X-axis, the estimated temperature could be in the range of 30.5 °C to 35 °C, indicating the temperature of the thermistor when its resistance is 1000 Ω.
Step 5
What does your graph tell you about the relationship between the resistance of a thermistor and its temperature?
Answer
The graph indicates that there is an inverse relationship between the resistance of the thermistor and its temperature. As the temperature increases, the resistance decreases significantly, demonstrating that thermistors are sensitive temperature sensors that exhibit decreased resistance at higher temperatures.