Question

Consider two copper wires of the same length. One has twice the cross-sectional area of the other. How do the resistances of these two wires compare? Consider two copper wires of the same length. One has twice the cross-sectional area of the other. How do the resistances of these two wires compare? Both wires have the same resistance. The thicker wire has twice the resistance of the shorter wire. The thicker wire has half the resistance of the shorter wire. none of the given answers

Answer 1

Answer: a) when the cross section is doubled the resultant resistence is a half. This means the thicker wire have half resistence than the thinner wire.

Explanation: In order to explain this behaviur we have to consider the expresion for the resistence which is given by:

`R=(\epsilon o  L)/(A)` where L and A are the length and the cross section for the wire, respectively.

From this expresssion we can conclude the above, this means

R=εo*L/A if A is now 2A we have

R' = εo*L/2*A= R/2