Four identical cells of emf `epsilon` and internal resistance r are to be connected in series. Suppose, if one of the cell is connected wrongly, then the equivalent emf and effective internal resistance of the combination is

Options

A. 2E and 4r
B. 4E and 4r
C. 2E and 2r
D. 4E and 2r

Answer

A

Explanation

Total internal resistance does not change
`therefore " " R'=4r`
Net emf is `" " E'=E[n-2m]`
Here, n = total number of cells = 4
m = wrong connection = 1
`E'=E[4-2]`
i.e., `E'=2E`