Question

The current flowing through the resistance R in the circuit in the figure has the form 2 cos 4t, where R is ____________

(a) (0.18 + j0.72)

(b) (0.46 + j1.90)

(c) – (0.18 + j1.90)

(d) (0.23 – 0.35 j)

This question was addressed to me in semester exam.

This interesting question is from Advanced Problems Involving Complex Circuit Diagram topic in chapter Network Theory and Complex Circuit Diagram of Network Theory

Answer 1

Correct option is (d) (0.23 – 0.35 j)

The explanation is: Inductor is not given, hence ignoring the inductance. Let I1 and I2 are currents in the loop then,

I1 = \(\frac{2 cos⁡4t}{3}\)

= 0.66 cos 4t

Again, I2 = \(\frac{-j X 4 X 0.75 I_1}{3.92-2.56j}\)

= (0.23 – 0.35j) cos 4