Question

If there are (N-2+3) Node-Voltage equations then the number of nodes in the circuit are __________

(a) N+2

(b) N+1

(c) N

(d) N-1

The question was posed to me in an international level competition.

This intriguing question comes from The Node-Voltage Method and Dependent Sources and Some Special Cases topic in section Techniques of Circuit Analysis of Electric Circuits

Answer 1

Correct answer is (a) N+2

To explain I would say: If there are n nodes then n-1 nodal equations are required to describe the circuit. So, given N-2+3 i.e. N+1 nodal equations and it implies N+2 nodes.