Physics · Oct / Nov 2020 · Paper 61 · Question 4
0625
As printed in the paper
The question as text
A student investigates the resistances of different wires. Plan an experiment to investigate the resistances of wires made from different metals. Resistance is calculated using the equation R = V I . The following apparatus is available: ammeter voltmeter power supply metre rule a selection of wires made from different metals. You can also use other apparatus and materials that are usually available in a school laboratory. In your plan, you should: • write a list of suitable metals for the wires you will investigate • draw a diagram of a suitable electrical circuit using standard electrical symbols • explain briefly how to carry out the investigation • state the key variables to keep constant • draw a table, or tables, with column headings, to show how to display your readings (you are not required to enter any readings in the table).
Read automatically from the paper; the printed page above is exact.
Show the answer and mark scheme
MP1
Correct circuit diagram to include test wire, power source, ammeter and voltmeter
MP2
Correct symbols used for ammeter and voltmeter.
MP3
At least 3 different metals (or alloys) suggested
MP4
Measure potential difference and current. Work out resistance
MP5
Repeat with at least two more wires of different material.
MP6
Key variables:
Any one from:
Length of wire
Diameter / thickness / cross-sectional area of wire
MP7
Table with columns for material, potential difference, current and resistance with units V, A, Ω.
Additional graph notes:
Note: The principle to apply here is ‘could I draw a significantly better line, using these points, under examination conditions?’ If the answer is definitely ‘yes’, do not award the mark.
Note: If candidate’s scale consists of actual readings at equal intervals this will produce a perfect straight line! The only mark available in this case is the first (axes right way round and labelled) So maximum 1.
If axes are wrong way round, the other 3 marks are still available.
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