4-2. Find the equivalent resistance (Ω) between points A and B in the figure if R1 = 2.48 Ω, R2 = 7.85 Ω, R3 = 3.69 Ω, R4 = 1.34 Ω, and R5 = 2.85 Ω.
4-3. (a) Find the equivalent resistance (Ω) of the group of resistors in the figure if R1 = 2550 Ω, R2 = 4890 Ω, and R3 = 2380 Ω. (b) If these resistors are connected to a V = 12.0-V battery as shown in the figure, find the potential difference (V) across R2. (c) Find the current (mA) flowing through R2. Hint: In part (b), use V = IReq to find the total current I from the battery. This is also equal to the current through R3, i.e., I3 = I. Using V3 = I3R3, you can find the voltage V3 across R3. Since V = V3 + V2 (loop rule), you can finally find the voltage V2 across R2.