Q.
A potentiometer circuit is set up as shown. The potential gradient, across the potentiometer wire, is $k\ volt/cm$ and the ammeter, present in the cicuit, reads $1.0\ A$ when two way key is switched off. The balance points, when the key between the terminals (i) 1 and 2 (ii) 1 and 3, is plugged in, are found to be at lengths $l_{1}\ cm$ and $l_{2}cm$ respectively. The magnitudes, of the resistors $R$ and $X,$ in ohms, are then, equal, respectively, to
A) $kl_{1}$ and $kl_{2}$
B) $k\left( l_{2} - l_{1} \right)$ and $kl_{2}$
C) $kl_{1}$ and $k(l_{2} - l_{1})$
D) $k\left( l_{2} - l_{1} \right)$ and $kl_{1}$
Explanation
(c) $R = kl_{1}$ and $R + X = kl_{2}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.