Question

Two batteries with e.m.f $12\text{V}$ and $13\text{V}$ are connected in parallel across a load resistor of $10\Omega .$ The internal resistances of the two batteries are $1\Omega$ and $2\Omega$ respectivey. The voltage across the load lies between

• A. $11.7\text{V}$ and $11.8\text{V}$
• B. $11.6\text{V}$ and $11.7\text{V}$
• C. $11.5\text{V}$ and $11.6\text{V}$
• D. $11.4\text{V}$ and $11.5\text{V}$

Answer 1

The correct option is C $11.5\text{V}$ and $11.6\text{V}$


From the junction law, we can write $\frac{x-12}{1}+\frac{x-13}{2}+\frac{x-0}{10}=0$
$10x-120+5x-65+x=0$
$16x=185$
$x=\frac{185}{16}=11.5625$
Which lies in between $11.5\text{V}$ and $11.6\text{V}$.