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If specific resistance of a potentiometer wire is 10^-7 Ωm, the current flow through it is 0.1 A and the cross-sectional area of wire is 10^-6 m^2 then potential gradient will be

1. 10^-2 volt/m
2. 10^-4 volt/m
3. 10^-6 volt/m
4. 10^-8 volt/m

Correct answer: 10^-2 volt/m

Solution

The potential gradient is given by V/L = (ρI)/A, where ρ is the resistivity, I is the current, and A is the cross-sectional area. Substituting the values: (10^-7 × 0.1) / 10^-6 = 10^-2 V/m.

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