Combinations of resistors are a regular 0625 Paper 5 electricity question. Build each circuit by hand: carry the resistors from the tray into the slots on the connection board, press the switch, read the meters, then open the switch before you rebuild. Work out what each circuit says about one resistor and whether the three are really identical. Allow about 20 minutes.
Past-paper referenceOriginal experiment, wording and numbers, written in the style of Cambridge IGCSE Physics 0625 Paper 5 (Practical Test), Question 2. It is not copied from a past paper.
Practise next: 0625/52 February/March 2024, Question 2 (circuits containing different combinations of three resistors) · official past papers
Practise next: 0625/53 May/June 2023, Question 2 (resistors added in parallel between P and Q) · official past papers
This type of experiment has come up 24 times (12 in Paper 5, the Practical Test, and 12 in Paper 6, the Alternative to Practical) in the past papers we checked. Show the list
Checked: Cambridge IGCSE Physics 0625 Papers 5 and 6, 2014 to 2025. Only the papers in our collection are listed, so the real number may be higher. Question papers are available from Cambridge.
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How this question is marked
Readings and table (a)
Headings with units, V and I recorded as the meters show them for each of the three circuits, and R = V / I to 2 or 3 significant figures.
Analysis (b), (c)
The resistance of one resistor from each circuit using your own values, and a conclusion that follows from how far apart they are.
Evaluation (d), (e)
Which arrangement gives the largest current and why, and opening the switch between readings.
Habits that save marks
Open the switch before you change the circuit, and between readings, so nothing heats up.
Series resistances add; parallel resistors have a smaller combined resistance than any one of them.
Record meters as they read, to the same number of decimal places every time.
The marking follows the conventions in published Cambridge mark schemes. The experiments, readings and wording on this page are our own.