Question

What is the resistance of a 7.4-m length of copper wire 1.2mm in diameter? The resistivity of copper is 1.68×10−8Ω⋅m.

Answer 1

know the formula?

Answer 2

is it R = V/A

Answer 3

I dont think its that one...

Answer 4

\(\Large R = \rho \dfrac{L}{A}\)

Answer 5

\(\rho \) is resistivity
L is Length
A is the area

Answer 6

since diameter is given, first you need to find Area
can you ?

Answer 7

do I use the formula for a cylinder?

Answer 8

A = 2 pi (1.2mm) + 2 pi (1.2mm) (7.4m)

Answer 9

i got 46.5

Answer 10

its the cross-sectional area only

A = \(\pi r^2 = \pi d^2/4\)

Answer 11

ohh so it is 1.13x 10^-6 =A

Answer 12

yes
good :)

Answer 13

so now you know all, \(\rho,L,A\)

Answer 14

for an answer i got 0.1100176991

Answer 15

R = (1.68x10^-8) (7.4 / 1.13x10^-6)

Answer 16

seems to be correct :)

Answer 17

is the unit ohm

Answer 18

yes, unit of resistance is ohm

Answer 19

thank you very much

Answer 20

welcome ^_^