The GATE Grind

GATE 2023 BM – Question 38

Electrical Circuits · Network Theorems · 2 marks · Multiple choice

In the shown circuit, the DC sources have voltages V₁ and V₂. To which expression is the power dissipated in the 60 kΩ resistor proportional?

Diagram for GATE 2023 BM question 38
  1. $(V_1+V_2)^2$
  2. $(3V_1+V_2)^2$
  3. $(2V_1+V_2)^2$
  4. $(V_1+2V_2)^2$

Practise this question in The GATE Grind →

Show answer and explanation

Correct answer: (C) $(2V_1+V_2)^2$

Explanation

Let the central voltage be V. Kirchhoff’s current law gives (V−V₁)/10+(V−V₂)/20+V/60=0, with resistances in kilohms. Multiplying by sixty gives 10V=6V₁+3V₂, so V=(3/10)(2V₁+V₂). Power is V²/60 kΩ and is therefore proportional to (2V₁+V₂)², C.

More Network Theorems questions

All Network Theorems questions →