Question : n identical cells, each of emf E and internal resistance r, are connected in series. Later on it was found out that two cells 'X' and 'Y' are connected in reverse polarities. Calculate the potential difference across the cell 'X'.
Doubt by Japjee
Solution :
Total number of cells = n
Net EMF
Eeq = E1+E2+E3+. . En
=E+E+E+E+. . . .E+(-E)+(-E)
=(n-4)E
Total Internal Resistance
req=nr [Resistance does not depend on polarity]
Net EMF
Eeq = E1+E2+E3+. . En
=E+E+E+E+. . . .E+(-E)+(-E)
=(n-4)E
Total Internal Resistance
req=nr [Resistance does not depend on polarity]
Here the cell X and Y are not giving out current but actually they are being charged by the other cells
So, potential difference across Cell X
V=Eeq+Ireq
V=E+[(n-4)E/nr)]r
V=Eeq+Ireq
V=E+[(n-4)E/nr)]r
