Question

In the circuit given below, the value of R in the circuit, when the current is zero in the branch CD is _________ (a) 10 Ω (b) 20 Ω (c) 30 Ω (d) 40 Ω This question was addressed to me in exam. Query is from Advanced Problems on Network Theory topic in chapter Network Theory and Complex Circuit Diagram of Network Theory Select the correct answer from above options network theory questions and answers, network theory questions pdf, network theory question bank, network theory gate questions and answers pdf, mcq on network theory pdf, gate network theory questions and solutions, network theory mcq Test , ies network theory questions, Network theory Questions for GATE EC Exam, Network Theory MCQ (Multiple Choice Questions)

Answer 1

Right option is (d) 40 Ω Explanation: The current in the branch CD is zero if the potential difference in the branch CD is zero. That is, VC = VD Or, V10 = VC = VD = VA × \frac{10}{15} VR = VA × \frac{R}{20+R} And V10 = VR ∴ VA × \frac{10}{15} = VA × \frac{R}{R+20} ∴ R = 40 Ω.