What is the SI unit for power?

What is the SI unit for power?

• A. Joules
• B. Watts
• C. Volts
• D. Amps

Answer: (B)

Power is the rate at which energy is transferred or work is done. Its SI unit is the watt, defined as one joule per second. In other words, if energy changes by one joule every second, the power is one watt. In electrical circuits, power can be found with P = V × I, showing how voltage and current together determine how much energy per unit time is being used or produced. Joules measure energy, not instantaneous power, so they aren’t the unit for power. Volts measure electric potential, and amps measure current, neither of which directly expresses how fast energy is transferred. For larger amounts of power, we use kilowatts, where 1 kW equals 1000 watts.

Power is the rate at which energy is transferred or work is done. Its SI unit is the watt, defined as one joule per second. In other words, if energy changes by one joule every second, the power is one watt. In electrical circuits, power can be found with P = V × I, showing how voltage and current together determine how much energy per unit time is being used or produced. Joules measure energy, not instantaneous power, so they aren’t the unit for power. Volts measure electric potential, and amps measure current, neither of which directly expresses how fast energy is transferred. For larger amounts of power, we use kilowatts, where 1 kW equals 1000 watts.