COMEDK2024Evening ShiftPhysicsCurrent ElectricityActual
Figure below shows a network of resistors, cells, and a capacitor at steady state. What is the current through the resistance 4 ?
Options
- A1.0 A
- B0.2 A
- CZero
- D0.5 A
Correct answer
B. 0.2 A
Step-by-step solution
At steady state, capacitor acts as open circuit no current through 3 F branch and the 2 top-left resistor. Simplified circuit has two active branches. Let left node be V_A , right node = 0 V (ground). The 6 V cell sets the middle wire at +6 V. Current through middle branch (via 2 V cell and 1 ): I₁ = (V_A + 2) - 6 1 = V_A - 4 Current through bottom branch (via 3 V cell and 4 ): I₂ = (V_A - 3) - 0 4 = V_A - 3 4 KCL at node A: (V_A - 4) + V_A - 3 4 = 0 4V_A - 16 + V_A - 3 = 0 5V_A = 19 V_A = 3.8 V I_ 4 = 3.8 - 3 4 =