A conductor has a diameter of 1.00mm and length of 2.00m. If the resistance of the material is 0.1Ω, 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
Correct Answer: Option D
Explanation
( R = frac{1}{a} p implies p = frac{R.a}{1} = frac{0.1 times 3.14}{2} left ( frac{10^{-3}}{2} right)^2 \
text{Therefore } p = frac{0.1 times 3.14 times 10^{-6}}{2 times 4} \
= 0.3925 times 10^{-7} text{ OR } -3.930 times 10 ^{-8}Ωm )