Question

The diameter of copper wire is 7.360 mm. Find the resistance of a 5 km length of such wire used for power transmission. (Specific resistance of wire = 1.720 x 10^-8 ohm meter) ​

Answer 1

2.05 Ω

Step-by-step explanation:

We are here given that the

• diameter= 7.360 mm = 0.7360 cm
• length of wire= 5km = 5000m
• specific resistance= 1.720 * 10-⁸ Ω m

We need to find out the resistance of the given wire . As we know that,

`\implies R = \rho (l)/(A) \\`

`\implies R =\rho ( l)/(\pi r^2) \\`

`\implies R =\rho (l)/(\pi (d^2)/(4)) \\`

`\implies R =\rho (4l)/(\pi d^2)\\`

substitute the respective values,

`\implies R = 1.720 * 10^(-8)* (4* 5000m)/(3.14* (0.74* 10^(-2)) \\`

`\implies\underline{\underline{ R = 2.05 \Omega }} \\`

and we are done!