Question

The resistivity of a resistor is 5 $\Omega -m$. Its length is 1$m$ and area of cross section is $2m{m}^2$. The resistance is .

• A. $2M\Omega$
• B. $2.5M\Omega$
• C. $4M\Omega$
• D. $5M\Omega$

Answer 1

The correct option is B $2.5M\Omega$

Given $\rho$, $l$ and $A$, we have a direct relation to find resistance.
$R=\frac{\rho l}{A}R=5\times \frac{1}{(2\times ({10}^{-3}{)}^2)}R=2.5M\Omega$