if m is a constant what is bound current density
Solution If the density (and mass) of the wire is constant, then so is its volume, lA = constant. Thus, R = Ïl= A = Ïl 2 =l A = constant Ã l 2, and doubling l increases the resistance four times. Problem 35.A cylindrical iron rod measures 88 cm long and 0.25 cm in diameter.(a) Find its resistance. If a 1.5-V potentialdifference is applied between the ends of the rod, find (b) the current, (c) the current density, and (d) the electric field inthe rod. cylindrical iron rod measures 88 cm long and 0.25 cm in diameter. (a) Find its resistance. If a 1.5-V potentialdifference is applied between the ends of the rod, find (b) the current, (c) the current density, and (d) the electric field inthe rod.