n identical cells, each of emf `epsilon` and internal resistance r, are joined in series to from a closed circuit. One cell a is joined with reversed polarity. The potential difference across each cell, except A, is

Options

A. `(2n epsilon)/(n-2)`
B. `((n-2)epsilon)/(n)`
C. `((n-1)epsilon)/(n)`
D. `(2epsilon)/(n)`

Answer

D

Explanation

When one cell is wrongly connected in series, the emf of cells decreases by `2epsilon`, but internal resistance of cells remains the same for all the cells.
Current in the circuit is `I=((n-2)epsilon)/(nr)`
Potential difference across each cell is
`V=epsilon-Ir=epsilon-((n-2)epsilon)/(nr)xxr=(2epsilon)/(n)`