Which unit is used to measure power?

Which unit is used to measure power?

• A. Newton (N)
• B. Watt (W)
• C. Joule (J)
• D. Pascal (Pa)

Answer: (B)

Power is the rate at which energy is transferred or work is done. The unit that measures this rate is the watt, defined as one joule of energy transferred per second. So a device rated at 60 watts converts about 60 joules of energy each second. The other units refer to different quantities: the newton measures force, the joule measures energy or work, and the pascal measures pressure. You can also see why watt fits by dimensional analysis: power can be written as force times velocity, so watt = newton × meter per second, which simplifies to kg·m^2/s^3. This shows why the watt is the appropriate unit for power.

Power is the rate at which energy is transferred or work is done. The unit that measures this rate is the watt, defined as one joule of energy transferred per second. So a device rated at 60 watts converts about 60 joules of energy each second. The other units refer to different quantities: the newton measures force, the joule measures energy or work, and the pascal measures pressure. You can also see why watt fits by dimensional analysis: power can be written as force times velocity, so watt = newton × meter per second, which simplifies to kg·m^2/s^3. This shows why the watt is the appropriate unit for power.