• # question_answer A constant voltage is applied between the two ends of a metallic wire. If both the length and the radius of the wire are doubled, the rate of heat developed in the wire [MP PMT 1996] A)            Will be doubled                   B)            Will be halved C)            Will remain the same        D)            Will be quadrupled

$H\propto \frac{1}{R}$ (If V = constant) Þ $\,\frac{{{H}_{1}}}{{{H}_{2}}}=\frac{{{R}_{2}}}{{{R}_{1}}}$$=\frac{{{l}_{2}}{{A}_{1}}}{{{l}_{1}}{{A}_{2}}}$$=\frac{{{l}_{2}}r_{1}^{2}}{{{l}_{1}}r_{2}^{2}}$ Þ ${{H}_{2}}=2{{H}_{1}}$