A conductor has a diameter of 1.00mm and length of 2.00m. If the resistance of the material is 0.1\Omega, the resistivity is
A
2.55 * 105 Ωm
B
2.55 * 103 Ωm
C
3.93 * 10-6 Ωm
D
3.93 * 10-8 Ωm
Verified Correct Answer: D.
Physical Principles & Numerical Solution
\( R = \frac{\rho L}{A}\) \(\implies \rho\) = \(\frac{R.A}{L}\) = \(\frac{0.1 \times 3.14}{2} \left ( \frac{10^{-3}}{2} \right)^2\)
\(\therefore\) \(\rho\) = \(\frac{0.1 \times 3.14 \times 10^{-6}}{2 \times 4}\)
= 0.3925 x 10\(^{-7}\) OR 3.930 x 10 \(^{-8}\)\Omegam
Source: Myschool Past Questions Archive (Record #41387)