Calculate the resistance of iron if

Homework Statement

A rectangle bar of iron is $$2cm$$ by $$2cm$$ in cross section. Calculate its resistance if the resistivity of iron is $$11 \times 10^{-8}\Omega{m}$$.

Homework Equations

$$R = \frac{Pl}{A}$$

The Attempt at a Solution

$$R = \frac{Pl}{A}$$

$$A = 2 \times 2 \times 10^-4 = 4 \times 10^{-4}m$$
$$P = 11 \times 10^{-8}\Omega{m}$$

How is it possible to find the resistance If I don't have the length?

G01
Homework Helper
Gold Member

How is it possible to find the resistance If I don't have the length?

It isn't.

Maybe they are looking for the resistance per unit length:

$$\frac{R}{\ell}=\frac{\rho}{A}$$