Q. The resistance of copper wire of diameter=2 mm is of the order of
A) $0.1\ \Omega m^{- 1}$
B) $0.1\ \Omega{km}^{- 1}$
C) $1\ \Omega m^{- 1}$
D) $1\ \Omega\ km^{- 1}$
Explanation
(a) From $R = \rho\frac{l}{a} = \frac{\rho l}{\pi D^{2}/4}$, when $l = 1$ m,
$D = 2\ $mm, $R = 0.1\ \Omega$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.