A1):** This identifies the constant current between $2.5\\ \\mathrm{V}$ and $3.0\\ \\mathrm{V}$, directly contradicting the claim that it continues to increase throughout. This is the third of the three available marks.","highlights":[{"text":"| 2.5 | 4.0 |\n| 3.0 | 4.0 |","location":"specification"}]}]}],"generatedAt":"2026-07-22T12:07:52.407Z","modelVersion":"gpt-5.6-terra+diagrams-1","explanationVersion":"v3"},"options":[]}],"options":[],"explanation":null,"firstAttemptFullMarks":null},{"id":"57174e8b-4a0d-4501-98c5-e82d2b5e9f0b","revisionId":"e352cf30-2f9e-495c-a289-93a3919f2632","questionNumber":null,"questionType":"LA","specification":"An engineer designs a test circuit to calibrate a negative temperature coefficient (NTC) thermistor, as shown in the diagram below.\n\n![Thermistor calibration circuit](https://assets.mathsgenie.co.uk/aqa-qb/0671efcc-3dd8-44de-af47-534ea2bd2c57.png)","difficulty":7,"difficultyBand":"medium","totalMarks":2,"sourceTitle":null,"calculatorUse":null,"parts":[{"id":"bc841ddc-866e-40ca-accb-9c6709a94d12","label":null,"content":"Explain how the variable resistor is used to prevent self-heating of the thermistor during the calibration process.","markscheme":"- Adjust the variable resistor to a high resistance value M1\n- This reduces the current flowing through the circuit, which decreases the rate of electrical energy dissipated as heat ($P = I^2 R$) in the thermistor, keeping its temperature stable A1","marks":2,"order":0,"markingRubric":null,"explanation":{"methods":[{"id":"limit_current","label":"Limit the current","steps":[{"type":"text","order":0,"title":"Set a high resistance","content":"Set the variable resistor to a **high resistance**. **This earns M1.**\n\nA larger total resistance reduces the current in this series circuit. The thermistor therefore dissipates less power as heat, using $P=I^2R$, so its temperature stays stable rather than increasing because of self-heating. **This explanation earns A1.**","highlights":[{"text":"variable resistor","location":"specification"},{"text":"prevent self-heating of the thermistor","location":"specification"}]}]}],"generatedAt":"2026-07-22T12:10:22.111Z","modelVersion":"gpt-5.6-terra+diagrams-1","explanationVersion":"v3"},"options":[]}],"options":[],"explanation":null,"firstAttemptFullMarks":null},{"id":"5996e60c-2f80-4fd7-b5ab-86820d121a17","revisionId":"5e41994e-1c34-4a4b-bbea-8b1f22f9d3bd","questionNumber":null,"questionType":"LA","specification":"A student wants to investigate the electrical properties of a nichrome wire. They are provided with a low-voltage DC power supply, a switch, an ammeter, a voltmeter, connecting leads with crocodile clips, and a $1.0\\text{ m}$ length of nichrome wire taped to a metre ruler.","difficulty":3,"difficultyBand":"medium","totalMarks":3,"sourceTitle":null,"calculatorUse":null,"parts":[{"id":"16c2985b-7085-45a5-961c-4769ca36381d","label":null,"content":"Draw a circuit diagram of the apparatus the student should set up to determine the resistance of exactly $40\\text{ cm}$ of the nichrome wire.\n\nYour circuit diagram must use standard electrical symbols for all components.","markscheme":"- Ammeter drawn in series with the resistance wire, using the correct symbol (circle with an 'A') B1\n- Voltmeter drawn in parallel across the active $40\\text{ cm}$ portion of the resistance wire, using the correct symbol (circle with a 'V') B1\n- A complete, correct series circuit containing the DC power supply, switch, ammeter, and resistance wire, with all standard symbols drawn correctly B1","marks":3,"order":0,"markingRubric":null,"explanation":{"methods":[{"id":"series_parallel_circuit","label":"Series circuit with parallel voltmeter","steps":[{"type":"text","order":0,"title":"Select the wire length","content":"Put one crocodile clip at $0\\text{ cm}$ and the other at $40\\text{ cm}$. These two clips make the active length exactly $40\\text{ cm}$; the remaining $60\\text{ cm}$ must not be part of the circuit.","highlights":[{"text":"exactl

Resistance and circuit components

Question 18

Resistance and circuit components Questions

Resistance and circuit components

Question 18

Resistance and circuit components Questions