question_answer

In the circuit shown below E1 = 4.0 V, R1= 2 W, E2 = 6.0 V, R2 = 4 W and R3 = 2 W.  The current  I1 is                [MP PET 2003]

A)            1.6 A

B)            1.8 A

C)            1.25 A

D)            1.0 A

Correct Answer: B

Solution :

                   Applying Kirchhoff?s law for the loops (1) and (2) as shown in figure For loop (1) \[-2{{i}_{1}}-2({{i}_{1}}-{{i}_{2}})+4=0\] Þ \[2{{i}_{1}}-{{i}_{2}}=2\]       ?(i) For loop (2)  \[-2({{i}_{1}}-{{i}_{2}})+4{{i}_{2}}-6=0\] Þ \[-{{i}_{1}}+3{{i}_{2}}=3\]     ?(ii) On solving equation (i) and (ii) \[{{i}_{1}}=1.8A\].