A resistor is made out of a copper wire having a length L. When the ends of the

Question

A resistor is made out of a copper wire having a length L. When the ends of the wire are attached across the terminals of a battery having a constant voltage V0 across its terminals, a current I flows through the wire. If the wire were cut in half, making two wires of length L/2, and both wires were attached across the terminals of the battery (the right ends of both wires attached to one terminal, and the left ends attached to the other terminal), how much current would be drawn from the battery?

(A) 4I (B) 2I (C) I (D) I/2 (E) I/4

Explanation / Answer

For the original wire,

I = V/R

R is in propotional to length l

For wire with length l/2, resistnance = R/2

For single half wire,

I' = V/ (R/2) = 2I

There are two wires:

I" = 2*I'

= 2*2*I

= 4 I. (Answer)

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