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  2. Picosecond - Wikipedia

    en.wikipedia.org/wiki/Picosecond

    A picosecond (abbreviated as ps) is a unit of time in the International System of Units (SI) equal to 10 −12 or 11 000 000 000 000 (one trillionth) of a second. That is one trillionth, or one millionth of one millionth of a second, or 0.000 000 000 001 seconds. A picosecond is to one second, as one second is to approximately 31,688.76 years.

  3. Picometre - Wikipedia

    en.wikipedia.org/wiki/Picometre

    The picometre (international spelling as used by the International Bureau of Weights and Measures; SI symbol: pm) or picometer (American spelling) is a unit of length in the International System of Units (SI), equal to 1 × 10 −12 m, or one trillionth (⁠ 1 / 1 000 000 000 000 ⁠) of a metre, which is the SI base unit of length.

  4. Orders of magnitude (time) - Wikipedia

    en.wikipedia.org/wiki/Orders_of_magnitude_(time)

    1 ns: The time needed to execute one machine cycle by a 1 GHz microprocessor 1 ns: The time light takes to travel 30 cm (11.811 in) 10 −6: microsecond: μs One millionth of one second 1 μs: The time needed to execute one machine cycle by an Intel 80186 microprocessor 2.2 μs: The lifetime of a muon

  5. Water pollution - Wikipedia

    en.wikipedia.org/wiki/Water_pollution

    A practical definition of water pollution is: "Water pollution is the addition of substances or energy forms that directly or indirectly alter the nature of the water body in such a manner that negatively affects its legitimate uses." [1]: 6 Water is typically referred to as polluted when it is impaired by anthropogenic contaminants.

  6. Unit of time - Wikipedia

    en.wikipedia.org/wiki/Unit_of_time

    1/1000 d (0.001 d) 1.44 minutes, or 86.4 seconds. Also marketed as a ".beat" by the Swatch corporation. moment: 1/40 solar hour (90 s on average) Medieval unit of time used by astronomers to compute astronomical movements, length varies with the season. [4] Also colloquially refers to a brief period of time. centiday 0.01 d (1 % of a day)

  7. United States regulation of point source water pollution

    en.wikipedia.org/wiki/United_States_regulation...

    The difference with water pollution, however, is that the problems that cause local water quality issues differ from those that create regional air pollution problems. Discharges into water are difficult to measure and effects are dependent on a variety of other factors and vary with weather and location.

  8. Nonpoint source pollution - Wikipedia

    en.wikipedia.org/wiki/Nonpoint_source_pollution

    Nonpoint source (NPS) pollution refers to diffuse contamination (or pollution) of water or air that does not originate from a single discrete source. This type of pollution is often the cumulative effect of small amounts of contaminants gathered from a large area. It is in contrast to point source pollution which results from a single source.

  9. Femtosecond - Wikipedia

    en.wikipedia.org/wiki/Femtosecond

    A femtosecond is a unit of time in the International System of Units (SI) equal to 10 −15 or 11 000 000 000 000 000 of a second; that is, one quadrillionth, or one millionth of one billionth, of a second. [1] A femtosecond is to a second, as a second is to approximately 31.69 million years.