[2]
Use the equation to determine the S.I. base units for resistivity .
base units for .......................................... [2]
Fig. 18.1
The wire is uniform and has diameter 0.38 mm. The cell has electromotive force (e.m.f.) E and internal resistance r. The length of the wire between X and Y is L.
The student varies the length L and measures the current in the circuit for each length.
Fig. 18.2 shows the data points plotted by the student.
Fig. 18.2
gradient = ............................... A–1m–1 [2]
= .................................................. Ωm [2]
Fig. 18.3
According to the student, re-plotting the data points using the actual lengths of the wire will not affect the value of the resistivity obtained in (iii).
Explain why the student is correct.
[2]
Did this page help you?