Q. In given figure, the potentiometer wire $AB$ has a resistance of $5\ \Omega$ and length $10\ m.$ The balancing length $AM$ for the emf of $0.4\ V$ is
A) $0.4\ m$
B) $4\ m$
C) $0.8\ m$
D) $8\ m$
Explanation
(d) $E = \frac{e}{\left( R + R_{h} + r \right)}.\frac{R}{L} \times l \Rightarrow 0.4 = \frac{5}{(5 + 45 + 0)} \times \frac{5}{10} \times l$
$\Rightarrow l = 8\ m$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.