What length of the wire of specific resistance 48×10−8Ω- m is needed to make a resistance of 4.2Ω(diameter of wire =0.4mm)
1.A copper wire has diameter 0.5mm & reactivity of 1.6*10 to the power -8 ohm m.what will be the length of this wire to make its resistance 10 ohm ? How much does the resistance charge if the diameter is doubled?