question_answer

Four identical cells, each of emf 8 V and internal resistance \[2.5\,\Omega ,\] are connected in series and charged by a 100 V DC supply, using a \[24\,\Omega \] resistor in series.

Calculate the following

(i) charging current in the circuit

(ii) potential difference across the cells during recharging.

Answer:

There are four identical cells with each having \[8\,V.\] The total resistance due to cells \[=2.5\times 4=10\,\Omega \] (\[\therefore \]in series) charged by a \[100\,V\]DC supply with \[24\,\Omega \] resistor in series. By KVL, \[4\times 8-10\times i-24\times i+100=0\] (i) So, \[l\] through the circuit \[=2A\] As, the cells are in parallel connection with each other. (ii) Potential difference across the cells, \[V=10024i\]\[=100(24\times 2)=52\,V\]