Question

The resistivity of a given wire of cross sectional area 0.7mm is 4.9*10-4mm.Calculate the resistance of 2m length of the wire

Answer 1

Answer: $1.4\ \Omega$

Explanation:

Given

Cross-sectional area $A=0.7\ mm^2$

Resistivity $\rho =4.94\times 10^{-4}\ \Omega-mm$

Length of wire $l=2\ m\ or\ 2000\ mm$

Resistance is given by

$\Rightarrow R=\dfrac{\rho l}{A}\\\\\text{Insert values}\\\\\Rightarrow R=4.9\times 10^{-4}\times \dfrac{2000}{0.7}\\\\\Rightarrow R=1.4\ \Omega$