Topic: Network Theory
In the circuit shown below, the current through 10 $\Omega$ resistor is
(The circuit shows two parallel branches with 150 V sources and 20 $\Omega$ resistors each, connected across a 10 $\Omega$ resistor. The polarities of the 150 V sources oppose each other relative to the common node).
- A. 5 A
- B. 10 A
- C. -5 A
- D. None of these
Answer: D. None of these
Explanation: Using nodal analysis at node A:
$\frac{V_A - 150}{20} + \frac{V_A + 150}{20} + \frac{V_A}{10} = 0$
$V_A = 0~\text{V}$.
The current through the 10 $\Omega$ resistor is $I_{10\Omega} = V_A / 10 = 0~\text{A}$. Therefore, the correct answer is 'None of these'.