Question

The specific resistance of manganin is $50\times {10}^{-8}\Omega m$. The resistance of a manganin cube having length 50 cm is

• A. ${10}^{-6}\Omega$
• B. $2.5\times {10}^{-5}\Omega$
• C. ${10}^{-8}\Omega$
• D. $5\times {10}^{-4}\Omega$

Answer 1

The correct option is A ${10}^{-6}\Omega$

$R=\rho \frac{l}{A}=\frac{50\times {10}^{-8}\times 50\times {10}^{-2}}{(50\times {10}^{-2}{)}^2}={10}^{-6}\Omega$