How Does the Y-Intercept Help Calculate Resistivity in an L/R vs. L Graph?

[Deliria]

This is a suggested relationship between L/R and L

L/R = kl + A/P

P is the resistivity, A is the cross-sectional area and k is the constant for the circuit

Using the value of the y-intercept find a value for P with the appropriate unit

The graph of L/R against L had the intercept of 9 but I have no idea where that fits in. All I know is the answer must be in Ohms

How do I calculate P?

 

[rock.freak667]

L/R = kl + A/P

is in the form Y=MX+C

where C=A/p

from a graph of Y vs X, how would you find C?

 

[mgb_phys]

If the graph of L/R (y) against L (x) has an intercept of 9, you mean it crosses the y-axis (where x=0) at 9
Therefore 9 = 0 + A/P, so A/P is 9, from the intercept we don't have any info about the slope 'k'

From this you can't separate resistivity and A - you could have a very narrow gold wire (low P) or a thick carbon (high P) one with the same resistance, ie the same P/A

 

[Deliria]

Yes it crosses the y-axis at 9.
Is k the gradient?

I calculated A is 6.1 x 10⁻⁸ m² Is the equation possible now?