Find the resistance of a hollow cylindrical pipe of length 1m whose inner and outer radii are 10cm and 20 cm respectively.

Asked by M. Bhanu Ashwin | 23rd May, 2011, 04:11: PM

Expert Answer:

In this type of problem, we must divide the object whose resistance we are calculating into concentric elements of infinitesimal thickness dr. We start by using the differential form of replacing r for the distance variable: , where dR is the resistance of the element of thicknessdr and surface area A.In this example, we take as our representative concentric elements a hollow cylinder of pipe of length L=1m.Any current passes from inner conductor to outer one must past radially through the concentric elements, and the area  through which the current passes as A=2L (This is the curved surface area -circumference multiplied by length of our hollow cylinder of thickness dr). Hence the required resistance is 

Answered by  | 28th May, 2011, 02:21: PM

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