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AP EAMCET · PHYSICS · Current Electricity

In a potentiometer, the area of cross section of the wire is \(4 \mathrm{~cm}^2\), the current flowing in the circuit is 1 A and the potential gradient is \(7.5 \mathrm{Vm}^{-1}\), then the resistivity of the potentiometer wire is

  1. A \(3 \times 10^{-3} \Omega \mathrm{~m}\)
  2. B \(2 \times 10^{-6} \Omega \mathrm{~m}\)
  3. C \(4 \times 10^{-2} \Omega \mathrm{~m}\)
  4. D \(5 \times 10^{-4} \Omega \mathrm{~m}\)
Verified Solution

Answer & Solution

Correct Answer

(A) \(3 \times 10^{-3} \Omega \mathrm{~m}\)

Step-by-step Solution

Detailed explanation

In potentiometer, \(\mathrm{A}=4 \mathrm{~cm}^2=4 \times 10^{-4} \mathrm{~m}^2\) \(\mathrm{I}=1 \mathrm{~A}, \mathrm{k}=7.5 \mathrm{Vm}^{-1}\) \(\therefore\) Potential gradient, \(k=\frac{V}{l}=\frac{I_\delta}{A}\) \(\therefore\) Resistivity…