Circuit Diagram Physics Example 4

Solution

1. 1
   Branch 2 resistance: $R_{34} = R_3 + R_4 = 3 + 3 = 6 \text{ } \Omega$. Parallel: $R_p = \frac{R_2 \times R_{34}}{R_2 + R_{34}} = \frac{6 \times 6}{12} = 3 \text{ } \Omega$.
2. 2
   Total: $R_T = R_1 + R_p = 4 + 3 = 7 \text{ } \Omega$. Total current: $I = \frac{12}{7} \approx 1.71 \text{ A}$.
3. 3
   Voltage across parallel section: $V_p = IR_p = 1.71 \times 3 = 5.14 \text{ V}$. Current through $R_2$: $I_2 = \frac{V_p}{R_2} = \frac{5.14}{6} \approx 0.857 \text{ A}$.