Wattage is also referred to as emf.

• A. False
• B. True
• C. Sometimes
• D. Not specified

Answer: (A)

Power and electromotive force are different ideas. Emf, or electromotive force, is the driving potential a source provides, measured in volts, representing energy per unit charge available to push charges through a circuit. Wattage is the rate at which energy is transferred or used, measured in watts, and it’s found from P = V × I (voltage times current). So wattage is not emf. A battery with a 12 V emf can deliver power depending on the current and any losses inside the source; if 1 A flows with the terminal voltage at 12 V, that’s 12 W of power to the load, but if internal resistance drops the terminal voltage, the actual power is less. This shows emf and wattage are related but not the same thing.