Q. $AB$ is a wire of uniform resistance. The galvanometer $G$ shows no current when the length $AC = 20cm$ and $CB = 80cm.$ The resistance $R$ is equal to
A) $2\ \Omega$
B) $8\ \Omega$
C) $20\ \Omega$
D) $40\ \Omega$
Explanation
(c) By Wheatstone bridge, $\frac{R}{80} = \frac{AC}{BC} = \frac{20}{80} \Rightarrow R = 20\ \Omega$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.