Question

the external diameter of a 5 metre long hollow tube is 10cm and the thickness of its wall is 5mm. If the specific resistance of copper be 1.7*10 ki power -5 ohm metre, then determine its resistance.

solve it fast !! ​

Answer 1

Given,

$r_{1} = 4.5*10^{-2} m\\\\r_{2}= 5*10^{-2}m$

$\rho = 1.7*10^{-5} ohm m.$

l = 5 m.

Let the cross section area of the tube be A.

We know,

A = $\pi(r_{2}^{2} - r_{1}^{2})$

 

on putting the values,

$A = 3.14*[(5*10^{-2})^{2}-(4.5*10^{-2})^{2}]$

= $14.9*10^{-4}m^{2}$

∴ Resistance = $\rho\frac{l}{A}$

on putting the values,

= $\frac{1.7*10^{-5}*5}{14.9*10^{-4}}$

= 0.57* $10^{-1}$

= 0.057 ohm.

Answer 2

Answer:-

Given in the attachment