Solution:
Using \(R = \rho \frac{l}{A} = \rho \frac{l}{\pi (d/2)^2} \propto \frac{1}{d^2}\). Since diameter \(d_B = 3d_A\), the resistance \(R_B = \frac{R_A}{3^2} = \frac{81}{9} = 9 \Omega\).
A certain wire \(A\) has resistance \(81 \Omega\). The resistance of another wire \(B\) of same material and equal length but of diameter thrice the diameter of \(A\) will be
Leave a Reply