Which device most likely uses only alternating current (AC) during normal operation?

• A. A flashlight powered by alkaline cells
• B. A typical household ceiling fan plugged into a wall outlet
• C. A smartphone powered by its internal battery
• D. An automobile starter motor powered by a 12 V battery

Answer: (B)

Verified step by step guidance

1. Step 1: Understand the difference between alternating current (AC) and direct current (DC). AC periodically reverses direction, while DC flows in one constant direction.
2. Step 2: Identify the power source for each device. A flashlight powered by alkaline cells, a smartphone powered by its internal battery, and an automobile starter motor powered by a 12 V battery all use batteries, which provide direct current (DC).
3. Step 3: Recognize that a typical household ceiling fan plugged into a wall outlet receives power from the electrical grid, which supplies alternating current (AC).
4. Step 4: Conclude that the device most likely to use only AC during normal operation is the household ceiling fan, since it is directly connected to an AC power source.
5. Step 5: Summarize that devices powered by batteries operate on DC, while devices plugged into wall outlets typically operate on AC.