Question

Figure shows five dc sources(cells). Their emfs are shown in the figure. Emf of the battery AB is.

• A. $8$V
• B. $16$V
• C. $4$V
• D. $2$

Answer 1

The correct option is A $8$V

In series connection of batteries, when the positive end of a battery is connected to the negative end of another battery the total emf is the sum of the emfs of the two respective batteries. So summing over in the upper series circuit and lower series circuit we found that: $E_{up}=8V$ and $E_{down}=8V$.

Now we have two batteries with equivalent emf of 8V each and are connected with each other parallelly. When two batteries with same emf's are connected in parallel the net emf is the emf of a single battery with double capacity.

Hence, $E_{circuit}=8V$.