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The amount of electricity required to run a 1 W device for 1 s. The energy required to accelerate a 1 kg mass at 1 m/s 2 through a distance of 1 m. The kinetic energy of a 2 kg mass travelling at 1 m/s, or a 1 kg mass travelling at 1.41 m/s. The energy required to lift an apple up 1 m, assuming the apple has a mass of 101.97 g.
A unit of electrical energy, particularly for utility bills, is the kilowatt-hour (kWh); [3] one kilowatt-hour is equivalent to 3.6 megajoules. Electricity usage is often given in units of kilowatt-hours per year or other periods. [4] This is a measurement of average power consumption, meaning the average rate at which energy is transferred ...
The dimension of power is energy divided by time. In the International System of Units (SI), the unit of power is the watt (W), which is equal to one joule per second. Other common and traditional measures are horsepower (hp), comparing to the power of a horse; one mechanical horsepower equals about 745.7 watts.
The wall-plug efficiency is the measure of output radiative-energy, in watts (joules per second), per total input electrical energy in watts. The output energy is usually measured in terms of absolute irradiance and the wall-plug efficiency is given as a percentage of the total input energy, with the inverse percentage representing the losses.
Electric power is the rate at which electric energy is transferred by an electric circuit. The SI unit of power is the watt, one joule per second. Electric power, like mechanical power, is the rate of doing work, measured in watts, and represented by the letter P. The term wattage is used colloquially to mean "electric power in watts."
The energy in joules can be calculated from the capacitance (C) of the object and the static potential V in volts (V) by the formula E = ½CV 2. [27] One experimenter estimates the capacitance of the human body as high as 400 picofarads , and a voltage of 50,000 volts, discharged e.g. during touching a charged car, creating a spark with energy ...
This convention means that temperature and energy quantities have the same dimensions. [22] [23] In particular, the SI unit kelvin becomes superfluous, being defined in terms of joules as 1 K = 1.380 649 × 10 −23 J. [24] With this convention, temperature is always given in units of energy, and the Boltzmann constant is not explicitly needed ...
Like other measures of energy per charge, emf uses the SI unit volt, which is equivalent to a joule (SI unit of energy) per coulomb (SI unit of charge). [17] Electromotive force in electrostatic units is the statvolt (in the centimeter gram second system of units equal in amount to an erg per electrostatic unit of charge).