An engineer is designing a heating system and builds two prototype circuits. Each circuit is powered by an identical ideal voltage source and contains three identical resistive heating elements of resistance RRR.
Explain, in terms of current paths and electrical resistance, why Circuit Y has a lower total resistance than Circuit X.
A student investigates how the electrical resistance of a negative temperature coefficient (NTC) thermistor varies with temperature.
Explain, in terms of charge carriers, why the resistance of an NTC thermistor decreases as its temperature increases.
Design a circuit diagram that can be used to investigate how the resistance of the thermistor changes with temperature.
In your description, state how a cell, the thermistor, a voltmeter, an ammeter, and a variable resistor should be connected.
Describe how the student would use the circuit designed in (b)(ii) to investigate how the resistance of the thermistor changes over a range of temperatures from 20 ∘C20\ ^\circ\text{C}20 ∘C to 80 ∘C80\ ^\circ\text{C}80 ∘C.
42 exam-style questions on OCR GCSE Physics Simple circuits. Each one has a worked solution and a mark scheme showing where the marks go.