Consider two cells of emf $$ε_1$$​ and $$ε_2$$​ with internal resistances $$г_1$$​ and $$г_2$$​, respectively. The two cells are connected in parallel by connecting their positive terminals together and connecting their negative terminals together. The combination is equivalent to a single cell with emf given by:

Correct option is B

​$$\text{1. Given:} \\\quad \text{EMF of the two cells: } \epsilon_1 \text{ and } \epsilon_2 \\\quad \text{Internal resistances of the two cells: } r_1 \text{ and } r_2 \\\\\text{2. Formula for Equivalent EMF } (\epsilon_{eq}): \\\quad \epsilon_{eq} = r_{eq} \left( \frac{\epsilon_1}{r_1} + \frac{\epsilon_2}{r_2} \right) \\\quad \text{Where, } r_{eq} \text{ is the equivalent resistance of the two cells connected in parallel.} \\\\\text{3. Formula for Equivalent Resistance } (r_{eq}): \\\quad r_{eq} = \frac{r_1 r_2}{r_1 + r_2} \\\\\text{4. Substituting } r_{eq} \text{ into Equation (1):} \\\quad \epsilon_{eq} = \frac{\epsilon_1 r_2 + \epsilon_2 r_1}{r_1 + r_2}$$​​