Question

The specific resistance of a wire is \(\rho\), its volume is \(3m^3\) and its resistance is \(3\)ohms, then its length will be

• A.
• B.
• C.
• D.

Answer 1

The correct option is B

Volumn $=Al=3\Rightarrow A=\frac{3}{l}$
Now $R=\rho \frac{l}{A}\Rightarrow 3=\frac{\rho \times l}{3/l}=\frac{\rho l^2}{3}\Rightarrow l^2=\frac{9}{\rho }=\frac{3}{\sqrt{\rho }}$