The methods of standardization or calibration employed have much in common even in the cases that appear most diverse.
The joule (/ËdÊuËl/), symbol J, is a derived unit of energy in the International System of Units. It is equal to the energy transferred (or work done) to an object when a force of one newton acts on that object in the direction of its motion through a distance of one metre (1 newton metre or NÂ·m).
Power is the rate at which energy is transferred. It is not energy but is often confused with energy. The watt is the most commonly used unit of measure for power. It measures the rate of energy transfer. Click on a scenario number above to begin the interactive explainer. A watt equals a joule per second. If a smart phone uses five joules of energy every second, then the power of the phone is five joules per second, or five watts. The animation above demonstrates the difference between energy and power. Each slide in the animation will transfer energy at different rates for five seconds.