Current density in circular wire, J=1×105rA∕m3 ∴ Current, I=JA =1×105r×πr2=105πr3 =105×314×(2×10−4)3 [∵r=2mm=2×10−4m] =2512×10−7A The rate of thermal energy produced, P=VI =70×2512×10−7=1.76×10−4W Energy consumed, E=P×t =1.76×10−4×1000[∵t=1000s] =0.176J
