Two cells, having the same e.m.f., are connected in series through an external resistance R. Cell have internal resistances $r_1$ and $r_2$ ($r_1>r_2$) respectively. When the circuit is closed, the potential difference across the first cell is zero. The value of R is:-

Question

( A ) $r_1+r_2$
( B ) $\frac{ r_1+r_2} 2$
( C ) $r_1-r_2$
( D ) $\frac{ r_1-r_2} 2$

Comments

C apply Ohms law