question no. 268
Q268. An electrical cable of copper has just one wire of radius 9 mm. Its resistance is 5 ohm. The single copper wire of the cable is replaced by 6 different well insulated copper wires each of radius 3 mm. The total resistance of the cable will now be equal to
(A) 7.5 Ω (B) 45Ω
(C) 90 Ω (D) 270 Ω
(C.P.M.T. 1988)