Using Formula on Page 13: What Are the Rules?

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SUMMARY

The discussion focuses on the application of a specific formula for calculating resistance in a rectangular plate with dimensions LxWxT, as outlined on page 13 of the MIT course notes. It is established that the formula for resistance, given by ##\rho L/WT##, is applicable only when the current flows parallel to the axis and the geometry is uniform. The instructor emphasizes that the formula does not hold true when the current is not aligned with the defined geometry, particularly in cases where wires are attached at the center of the plate's area.

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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?
 

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