A potentiometer wire has a uniform potential gradient. The specific resistance of the material of the wire is $10^{-7}$ ohm-m, the current passing through it is 0.1 A and its cross-sectional area is $10^{-6} m^2$. What is the value of the potential gradient?
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → $10^{-2} Vm^{-1}$
The potential gradient (λ) is -
$λ=\frac{V}{L}=\frac{I×R}{L}$ [By ohm's law]
where,
I = Current in the wire
R = Resistance of the wire
L = Length of wire
A = Area of cross - section
$∴λ=\frac{I×ρ}{A}=\frac{0.1×10^{-7}}{10^{-6}}$
$=10^{-2}V/m$