Question

A copper wire of length 2 m has resistance 10 ohm. What would be the resistance of the wire if the wire is stretched such that the length becomes 6 m?

Answer 1

I got the new resistance as 90 ohm but am not sure of my calculation method....
Can someone help pls..............

Answer 2

\[R \alpha L\]
\[\Delta R \alpha \Delta L \]
therefore,
\[\frac{ \Delta R }{ R } = \frac{ \Delta L }{ L }\]

Answer 3

@kausarsalley
thanks for your help but I need to use the regular formula R=rho*l/A to prove this

Answer 4

@TuringTest
@.Sam.

Can u pls help with this???

Answer 5

if
\[R=\rho \frac{ l }{ A }\]
then it means that
\[R \alpha L\]
and if (assuming the change in cross-sectional area is negligible)
\[\Delta R = \rho \frac{ \Delta l }{ A }\]
then,
\[\Delta R \alpha \Delta l\]
but if you do not understand, its okay.....hope someone explains it better...(: