Question

Figure shows a part of an electric circuit. The potentials at the points a, b and c are 30V, 12V and 2V respectively. the currents through the 20 resistors will be.

• A. 0.2 A
• B. 0.6 A
• C. 0.4 A
• D. 1.0 A

Answer 1

The Correct Option is C

Let potential of the junction be \( x \) volts using junction law \( i_1 + i_2 + i_3 = 0 \). \[ x - 30 = \frac{x - 12}{10} \quad \text{and} \quad x - 2 = \frac{x - 12}{20} \] Solving for \( x \): \[ x = 20 \, \text{V}, \quad \text{current through} \, 20 \, \Omega \, \text{resistor} = \frac{20 - 12}{20} = 0.4 \, \text{A} \]