Which physical quantity is measured in watts ($W$)?

• A. Power
• B. Energy
• C. Voltage
• D. Force

Answer: (A)

Verified step by step guidance

1. Understand that the watt (W) is the SI unit used to measure a specific physical quantity related to energy transfer over time.
2. Recall that power is defined as the rate at which work is done or energy is transferred, mathematically expressed as \(P = \frac{E}{t}\), where \(P\) is power, \(E\) is energy, and \(t\) is time.
3. Recognize that energy is measured in joules (J), voltage in volts (V), and force in newtons (N), so these units do not correspond to watts.
4. Conclude that since watts measure how quickly energy is used or transferred, the physical quantity measured in watts is power.
5. Therefore, the correct answer is power, as it directly relates to the unit watt (W).