Question

calculate the resistance of 1m long copper wire of radius 14m resistivity of the copper is 1.72 x 10^-8 ohm

Answer 1

Answer:

R=resistivity ×length / area of cross section

Answer 2

$R = ρ \frac{l}{A}$

where R is resistance, ρ is resistivity, l is length and A is area of cross section

Given:- l = 1 m

. r = 14 m

. ρ = 1.72 × 10^-8

Solution:-

$R = ρ \frac{l}{\pi {r}^{2} }$

$\: \: \: \: \: \: \: \: \: \: = \frac{1.72 \times {10}^{ - 8} \times 1}{ \frac{22}{7} \times 14 \times 14}$

$\: \: \: \: \: \: \: \: \: = \frac{1.72 \times {10}^{ - 8} }{616}$

$\: \: \: \: \: \: \: \: \: \: = 0.00279 \times {10}^{ - 8}$

$\: \: \: \: \: \: \: \: \: \: = 2.79 \times {10}^{ - 11}$