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Question
What do you understand by the "resistivity" of a substance?
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Solution
We know that resistance , `R=(rhol)/A`
So resistivity, `rho=RA/l/`
When the area of cross-section, A is 1 m2 and the length of the wire, l is 1 m, resistance is equal to resistivity.
Resistivity may be defined as the resistance offered by a conductor of length 1 m and area of cross-section 1 m2.
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