A) \[2.0\times {{10}^{-4}}\Omega \,-m\]
B) \[4.1\times {{10}^{-4}}\Omega \,-m\]
C) \[8.2\times {{10}^{-4}}\Omega \,-m\]
D) \[2.0\times {{10}^{-3}}\Omega \,-m\]
Correct Answer: C
Solution :
Given that V = 115 V \[l=10\,m\] \[J=1.4\times {{10}^{4}}A/{{m}^{2}}\] \[r=0.30\,mm=0.3\times {{10}^{-3}}m\] \[J=\left( \frac{i}{A} \right)\] \[i=JA\] and \[R=\frac{V}{i}\] \[R=\frac{V}{JA}\] Now \[R=\frac{\rho l}{A}\] \[\frac{V}{JA}=\frac{\rho l}{A}\] \[\rho =\frac{V}{Jl}\] \[=\frac{115}{1.4\times {{10}^{4}}\times 10}\] \[=82.14\times {{10}^{-5}}\] \[=8214\times {{10}^{-4}}\Omega -m\]
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