The external diameter of a 314 m long copper tube is 1.2 cm and the internal diameter is 1 cm. calculate its resistance if the specific resistance of copper is `2.2xx10^(-8)` ohm-metre.

Options

A. `2.0xx10^(-1)ohm`
B. `4.4xx10^(-2)ohm`
C. `3.14xx10^(-2)ohm`
D. `2.2xx10^(-2)ohm`

Answer

1

Explanation

Given `rho=2.2xx10^(-8)` ohm-metre
`l=314m,D=1.2xx10^(-2)m,D_(1)=1.0xx10^(-2)m`.
`R=(rhol)/((pi)/(4)(D^(2)-D_(1)^(2)))rArrR=(4xx2.2xx10^(-8)xx314)/(pi(1.2^(2)-1.0^(2))xx10^(-4))`
`=4 xx5xx1 0^(-2)Omega=2xx10-1Omega`.