Calculate the resistance of iron if

[looi76]

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]

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:

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

 

[Moetasim]

To calculate the resistance, you need to know the length of the iron bar. Without this information, it is not possible to accurately calculate the resistance. I would suggest checking the given information again or asking for clarification from the person who assigned the homework. If the length is not provided, you may need to make an assumption or use an average length for iron bars in order to calculate the resistance.