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  2. Power (physics) - Wikipedia

    en.wikipedia.org/wiki/Power_(physics)

    In the International System of Units, the unit of power is the watt, equal to one joule per second. Power is a scalar quantity. Specifying power in particular systems may require attention to other quantities; for example, the power involved in moving a ground vehicle is the product of the aerodynamic drag plus traction force on the wheels, and ...

  3. Per-unit system - Wikipedia

    en.wikipedia.org/wiki/Per-unit_system

    In the power systems analysis field of electrical engineering, a per-unit system is the expression of system quantities as fractions of a defined base unit quantity. . Calculations are simplified because quantities expressed as per-unit do not change when they are referred from one side of a transformer to t

  4. Watt - Wikipedia

    en.wikipedia.org/wiki/Watt

    Power is the rate at which energy is generated or consumed and hence is measured in units (e.g. watts) that represent energy per unit time. For example, when a light bulb with a power rating of 100 W is turned on for one hour, the energy used is 100 watt hours (W·h), 0.1 kilowatt hour, or 360 kJ. This same amount of energy would light a 40 ...

  5. Intensity (physics) - Wikipedia

    en.wikipedia.org/wiki/Intensity_(physics)

    In physics and many other areas of science and engineering the intensity or flux of radiant energy is the power transferred per unit area, where the area is measured on the plane perpendicular to the direction of propagation of the energy. [a] In the SI system, it has units watts per square metre (W/m 2), or kg⋅s −3 in base units.

  6. Poynting vector - Wikipedia

    en.wikipedia.org/wiki/Poynting_vector

    In physics, the Poynting vector (or Umov–Poynting vector) represents the directional energy flux (the energy transfer per unit area, per unit time) or power flow of an electromagnetic field. The SI unit of the Poynting vector is the watt per square metre (W/m 2); kg/s 3 in base SI units.

  7. Electric power - Wikipedia

    en.wikipedia.org/wiki/Electric_power

    Electric power is the rate of transfer of electrical energy within a circuit.Its SI unit is the watt, the general unit of power, defined as one joule per second.Standard prefixes apply to watts as with other SI units: thousands, millions and billions of watts are called kilowatts, megawatts and gigawatts respectively.

  8. Power density - Wikipedia

    en.wikipedia.org/wiki/Power_density

    Power density, defined as the amount of power (the time rate of energy transfer) per unit volume, is a critical parameter used across a spectrum of scientific and engineering disciplines. This metric, typically denoted in watts per cubic meter (W/m 3 ), serves as a fundamental measure for evaluating the efficacy and capability of various ...

  9. Sound power - Wikipedia

    en.wikipedia.org/wiki/Sound_power

    Sound power or acoustic power is the rate at which sound energy is emitted, reflected, transmitted or received, per unit time. [1] It is defined [2] as "through a surface, the product of the sound pressure, and the component of the particle velocity, at a point on the surface in the direction normal to the surface, integrated over that surface."