Question

Determine the current flowing in the ammeter having 1Ω internal resistance connected in series with the 3Ω resistor as shown in the below circuit.

(a) 0.91

(b) 0.92

(c) 0.93

(d) 0.94

The question was asked at a job interview.

My question is based upon Compensation Theorem topic in chapter Useful Theorems in Circuit Analysis of Network Theory

Answer 1

Right option is (c) 0.93

Best explanation: Current through 3Ω resistor = 1.11A. So voltage drop across 1Ω resistor = 1.11×1 = 1.11V. Now the circuit can be modified as

Now current through 3Ω resistor = 0.17A. This current is opposite to the current calculated before. So ammeter reading = (1.11-0.17) = 0.94A.