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A student investigates how the resistance of a length of nichrome wire changes with temperature - Edexcel - A-Level Physics - Question 11 - 2023 - Paper 1
Question 11
A student investigates how the resistance of a length of nichrome wire changes with temperature. (a) The student takes measurements to determine the resistance of t... show full transcript
Worked Solution & Example Answer:A student investigates how the resistance of a length of nichrome wire changes with temperature - Edexcel - A-Level Physics - Question 11 - 2023 - Paper 1
Step 1
Draw a diagram of the circuit the student could use.
Answer
The circuit diagram should include:
- A power source (like a battery)
- The nichrome wire connected in series with an ammeter and a voltmeter.
- The ammeter should be placed in series with the wire to measure the current passing through it, while the voltmeter should be connected in parallel to measure the voltage across the wire.
- Ensure that wires are correctly connected, demonstrating a complete circuit.
Step 2
Describe how the student could determine the temperature of the wire.
Answer
The student can accurately determine the temperature of the wire by employing the following method:
- Use a Thermometer: Place a thermometer in the water bath to measure the temperature.
- Stir the Water: Stir the water to ensure uniform temperature distribution and allow the thermometer to read consistent values.
- Thermal Equilibrium: Ensure the wire is fully submerged and in thermal equilibrium with the water, which allows for accurate temperature readings.
- Minimize Heat Loss: Keep the insulation around the wire to reduce heat loss, ensuring the measured temperature reflects the wire's actual temperature.
Step 3
Explain, in terms of particle behaviour, why the resistance of the nichrome wire changes as temperature increases.
Answer
As the temperature of the nichrome wire increases, several key particle behaviour changes occur:
- The kinetic energy of the lattice ions increases, leading to more vigorous vibrations.
- This increased motion results in a higher frequency of collisions between conducting electrons and these vibrating ions, which hinders the flow of electrons.
- The drift velocity of the electrons decreases due to these more frequent collisions, which leads to an increase in electrical resistance.
- Consequently, as temperature increases, the resistance of the nichrome wire increases due to the increasing difficulty for electrons to pass through the wire.