How Does Changing Length and Area Affect the Resistance of Copper Wires?

[zelda1850]

Homework Statement

a copper wire of length of length L and cross sectional area A has resistance R. A second copper wire at the same temperature has a length of 2L and a cross sectional area of 1/2 A. what is the resistance of the second copper wire?

Homework Equations

R = pL/A

L = 2
A = 1/2
p = how do i find p

The Attempt at a Solution

p stand for resistivty but how do i know it in this problem

 

[rl.bhat]

In the relevant equation replace L by 2L and A by A/2 to get new resistance.

 

[zelda1850]

oh should the answer come out to be 1R

 

[ideasrule]

yes.

 

[rl.bhat]

oh should the answer come out to be 1R

No.
New resistance R' = ρ*2L/A/2 = ...?

 

[zelda1850]

i think p would be 1.72 x 10 exponent -8 since it is on copper
so i do 1.72x10 exponent -8 * 2 m/ 2 a is that the right equation?