Question

The current I, as shown in the figure below, is ________

(a) 3 A

(b) 2 A

(c) 1 A

(d) 0

The question was asked in quiz.

Question is taken from Norton’s Theorem Involving Dependent and Independent Sources topic in section Useful Theorems in Circuit Analysis of Network Theory

Answer 1

Correct option is (c) 1 A

The best explanation: The 3 Ω resistance is an extra element because voltage at node B is independent of the 3 Ω resistance.

I1 = \(\frac{3}{2+1}\) = 1 A        (B -> A)

The net current in 2 Ω resistance is I = 1 – I1

= 2 – 1 = 1 A   (A -> B).