Current - 3rd Feb'16

Question

!!n!! identical cells, each of emf !!E!! and internal resistance !!r,!! are joined in series to form a closed circuit.

The potential difference across any one cell is:

(a) !!E !!

(b) !!E/n!!

(c) !!(n-1)/n E!!

(d) Zero

Solution

Current in circuit, !!i = (nE)/(nr)= E/r!!

The equivalent circuit of one is shown in figure.

Potential difference across the cell !!= V_A-V_B= -E+ir!!

!!=> V_A-V_B= -E + (E/r)r= -E+E=0!!

Therefore, option (D) is correct .