Q. Two similar accumulators each of emf E and internal resistance r are connected as shown in the following figure. Then, the potential difference between x and y is
A) 2E
B) E
C) Zero
D) None of these
Explanation
(c) From Kirchhoff’s second law
$V = \sum ir\ \ \ \ \ \ \ \ \ $(for closed mesh)
Where V is potential difference, $i\ $the current and $r$ the resistance.
∴ $E + E = Ir + Ir = 2Ir$
$or\ \ \ \ \ I = \frac{E}{r}\ \ \ \ \ldots.(i)$
$V_{x} - V_{y} = E - Ir$
Putting the value of I from Eq (i), we get
$V_{x} - V_{y} = E - \frac{E}{r} \times V = 0$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.