Question

Derive the expression for the resistivity of a substance and give the meaning of each symbol which occurs in it.

Answer 1

we know resistance of conductor depends on following factor :-

1) length of conductor
2) area of cross section.

so using this ...


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hope it will help u

Answer 2

'R' is directly proportional to 'l'
R is inversely proportional to A
Here 'l' is length of substance and A is area of cross section .therefore R is proportional to l/A
Or R = constant * l/A
Constant is known as resistivity therefore resistivity =R x A/l .