a. currents, greatest to least: C, B, A. b. voltages, greatest to least: A = B = C.
Work Step by Step
a. In a simple parallel circuit, the sum of the branch currents add up to the total current supplied by and flowing through the voltage source. This is Rule 3 for parallel circuits, on page 444, and discussed on pages 443-444. This is also illustrated in Figure 23.18. This means that the current through the battery is the greatest of all. We also conclude that Branch B carries more current than branch A. In branch A, the bulbs are in series and share the voltage. The voltage across the one bulb in branch B is twice the voltage across each of the bulbs in the top branch, A. Therefore, twice the current flows in branch B compared to branch A. b. For two or more devices connected in parallel, the voltage is the same across each device. This is Rule 1 for parallel circuits, on page 444, and discussed on pages 443-444. Consider the top branch as one device. We see that the voltage across each branch is the same as the battery voltage.