Resistance of wire having diameter 2 mm and length 100 cm is 0.7 `Omega`, so resistivity of wire = .....

Options

A. 14.4 `mu Omega` m
B. `22 mu Omega `m
C. `1.1 mu Omega` m
D. `0.22 mu Omega` m

Answer

B

Explanation

`2.2 mu Omega `m
R = `(rho l)/(pi r^(2))`
`rho = (pi r^(2) R)/(l) = (22)/(7) xx ((10^(-3))^(2) xx 0.7)/(1)`
= `2.2 xx 10^(-6) Omega m = 2.2 mu Omega` m