Not sure about second part of this question:
Current I through a wire of resistivity p varies with length L, area of cross-section A and pd V in accordance with the equation I = VA/pL.
Sketch a graph of I against a) V , b) L , c) 1/L
Explain how you would determine the resistivity from the graph of I against a) V b) 1/L
So the graph of I against V is a straight line graph where the gradient = A/pL.
Can resistivity be found by calculating the gradient and rearranging to get p = AL/gradient?
And the graph of I against 1/L is a straight line graph with gradient = VA/p and you could rearrange this to get p = VA/gradient but V isn't a constant so how would it work?
...for the 2nd time this year