Question

Two wires A and B of the same material have their lengths in the ratio 1:2 and cross-section areas in the ratio 2:3. If the resistance of wire A be 12 $\Omega$ then calculate the resistance of wire B?

Answer 1

Let Length of wires A and B be x and 2x
Let Area of cross -section A and B be 2y and 3y respectively.
For wire A,
$12=\frac{\rho \times x}{2y}\Rightarrow 24=\frac{\rho \times x}{y}And,R_B=\frac{\rho \times 2x}{3y}=24\times \frac{2}{3}=16\Omega$