The rate of energy transfer or the rate at which work is performed is called

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

Answer: (A)

Power is the rate at which energy is transferred or work is done. If you complete more work in a given amount of time, the power is higher. Mathematically, power equals work divided by time (or energy change over time), with the standard unit of one joule per second, called the watt. In mechanics, power can also be written as P = F · v, showing that how hard you push and how fast you move together determine the rate of energy transfer.

Wavelength is the spatial distance between successive peaks of a wave, so it describes position in space, not rate. Energy is the total amount of work that can be or has been done, not how quickly it happens. Force is a push or pull that can cause motion, but by itself it doesn’t specify how quickly energy is transferred.