• # question_answer  The circuit in figure shows two cells connected in opposition to each other. Cell ${{E}_{1}}$ is of emf 6V and internal resistance $2\,\Omega$ the cell  is of emf 4V and internal resistances $8\,\Omega .$ Find   (i) effective resistance of the circuit (ii) effective emf of the two cells and current in the circuit (iii) the potential difference between the points A and B.

(i) Consider the given circuit as shown below, Effective resistance $2\,\Omega +8\,\Omega =10\,\Omega$ (ii) Effective emf of two cells $=6-4=2\text{ }V,$ so the electric current is given by $\Rightarrow$   $I=2/10=0.2\,A$ along anti-clokwise direction, since ${{E}_{1}}>{{E}_{2}}.$ (iii) The direction of flow of current is always from high potential to low potential. Therefore, ${{V}_{B}}>{{V}_{A}}.$ $\Rightarrow$   ${{V}_{B}}-4V-(0.2)\times 8={{V}_{A}}$ Therefore,          ${{V}_{B}}-{{V}_{A}}=5.6V$