Two sources of equal emf are connected to an external resistance R. The internal resistances of the two sources are R1 and R2 (R2>R1). If the potential difference across the source having internal resistance R2 is zero, then
-
-
R = R2-R1
-
-
B.
R = R2-R1
The equivalent resistance of the circuit
Req = R1 + R2 + R
I = 2E/ R1 +R2 +R
according to the questions
-(VB-VA) = E- IR2
0 = E- IR2E= IR2
E = 2ER2/R1+R2+R
R1+R2+R =2R2
R= R1-R2