Two cables of copper are of equal lengths. One of them has a single wire of area of cross-section A, while other has 10 wires of cross-sectional area A/10 each. Give their suitability for transporting A.C. and D.C. (a) only multiple strands for A.C., either for D.C. (b) only multiple strands for A.C., only single strand for D.C. (c) only single strand for D.C., either for A.C. (d) only single strand for A.C., either for D.C.

Answer: (a). Due to skin effect, AC flows mostly near the surface of a conductor. Ten thin strands give much more surface area than one thick wire, so they suit AC. DC spreads over the whole cross-section; both cables have the same total area A, so either works for DC. So the answer is (a).

Two cables of copper are of equal lengths. One of them has a single… | NEET 1994 (AIPMT)

Q45NEET 1994 · AIPMTEasy

AC Basics: Peak, RMS & Average Values

Two cables of copper are of equal lengths. One of them has a single wire of area of cross-section $A$ , while other has 10 wires of cross-sectional area $A/10$ each. Give their suitability for transporting A.C. and D.C.

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Answer: (a)

Due to skin effect, AC flows mostly near the surface of a conductor.
Ten thin strands give much more surface area than one thick wire, so they suit AC.
DC spreads over the whole cross-section; both cables have the same total area $A$ , so either works for DC.
So the answer is (a).

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