• # question_answer $A\,\,{{5}^{o}}C$ rise in the temperature is observed in a conductor by passing some current. When the current is doubled, then rise in temperature will be equal to [BHU 2004] A)            ${{5}^{o}}C$                       B)            ${{10}^{o}}C$ C)            ${{20}^{o}}C$                     D)            ${{40}^{o}}C$

Using conservation of energy Supplied electric energy = absorbed heat energy Þ ${{i}^{2}}Rt=mST$ Þ $T\propto {{i}^{2}}$              (T - change in temperature) i.e. when i is doubled T will be four times i.e. $5\times 4={{20}^{o}}C$