`N` identical cells, each emf `E` and internal resistance `r` are joined in series. Out of `N` cells, `n` cells are wrongly connected i.e., their terminals are connected in reverse of the required for series connection `(n lt (N)/(2))`. Let `E_(0)` be the emf of resulting battery and `r_(0)` be its internal resistance. Then

Options

A. `E_(0) = (N - n) E, r_(0) = (N - n) r`
B. `E_(0) = (N - 2n) E, r_(0) = (N - 2n) r`
C. `E_(0) = (N - 2n) E, r_(0) = N r`
D. `E_(0) = (N - n) E, r_(0) = N r`

Answer

C

Explanation

(c ) For every cell that is wrongly connected, the emf decreases by `2 E`. However, internal resistance does not depend on the direction and therefore remains same for all cells.