# R = rho L / A

1. Mar 12, 2014

### oneplusone

2. Mar 12, 2014

### Simon Bridge

That sounds right - it only works for a nice geometry.

consider a rectangular plate LxWxT dimensions (length x width x thickness)
the resistance between opposite corners won't be $\rho L/WT$

Even if I attach the wires to the center of areas WxT, imagine W=T=1000m ... how does the current travel through the resistor then?