Concepts Of Physics MCQ Edition [Volume 2]PhysicsElectric Current in Conductors
A portion of an electric circuit is depicted in the figure. The electric potentials at points a , b , and c are given as 30 V , 12 V , and 2 V , respectively. Determine the currents flowing through each of the three resistors.
Options
- A1 A through 10 , 0.6 A through 20 , and 0.4 A through 30
- B2 A through 10 , 0.8 A through 20 , and 1.2 A through 30
- C1 A through 10 , 0.4 A through 20 , and 0.6 A through 30
- D0.5 A through 10 , 0.2 A through 20 , and 0.3 A through 30
Correct answer
C. 1 A through 10 , 0.4 A through 20 , and 0.6 A through 30
Step-by-step solution
Let the electric potential at the junction of the three resistors be V . Applying Kirchhoff's Current Law (KCL) at the junction, the sum of currents leaving the junction is zero. Assuming current flows from a to the junction, and from the junction to b and c : V_a - V 10 = V - V_b 20 + V - V_c 30 Given that V_a = 30 V , V_b = 12 V , and V_c = 2 V , we substitute these values into the equation: 30 - V 10 = V - 12 20 + V - 2 30 Multiplying the entire equation by 60 to clear the denominators: 6(30 - V) = 3(V - 12) + 2