Current Electricity · Question 34

Two cells of emfs 1 V and 2 V and internal resistances 2 and 1 , respectively, are connected in series with an external resistance of 6 . The total current in the circuit is I1. Now the same two cells in parallel configuration are connected to same external resistance. In this case, the total current drawn is I2. The value of ( I1I2 ) is x3. The value of x is .

Answer

4

Solution

Series: I1 = E1 + E2r1 + r2 + R = 1 + 22 + 1 + 6 = 13 A

Parallel: Eeq = E1r1 + E2r2 1r1 + 1r2 = 12 + 2 12 + 1 = 53 V

req = r1 r2r1 + r2 = 23

I2 = Eeqreq + R = 5/32/3 + 6 = 5/320/3 = 14 A

I1I2 = 1/31/4 = 43 = x3

x = 4

Answer: 4