Question

N identical cells are joined in series with two cells a and b with reversed polarities. Emf of each cell is e and internal resistance is r. Potential difference across cell a or b is : (n > 4)

Answer 1

$\huge\mathfrak{Answer}$

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Number of cells= n

EMF of each cell= E

and internal resistance of each cell= r

Total resistance in circuit= nr

One cell is joined in reverse, so total emf = nE-2E

Current in the circuit, I= nE-2E /nr

=E(n-2)/nr

Potential difference ,V = E- Ir

= E-(n-2)E×r /n×r

= E[1-(n-2)/n]

=2E/n

Answer 2

Answer:

it can be solved by using the formula

Inet =Enet /Rnet