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  2. Time in physics - Wikipedia

    en.wikipedia.org/wiki/Time_in_physics

    In the International System of Units (SI), the unit of time is the second (symbol: s). It has been defined since 1967 as "the duration of 9 192 631 770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium 133 atom", and is an SI base unit. [12]

  3. Unit of time - Wikipedia

    en.wikipedia.org/wiki/Unit_of_time

    The amount of time light takes to travel one Planck length. quectosecond: 10 −30 s: One nonillionth of a second. rontosecond: 10 −27 s: One octillionth of a second. yoctosecond: 10 −24 s: One septillionth of a second. jiffy (physics) 3 × 10 −24 s: The amount of time light takes to travel one fermi (about the size of a nucleon) in a ...

  4. Time - Wikipedia

    en.wikipedia.org/wiki/Time

    In physics, time is a fundamental concept to define other quantities, such as velocity. To avoid a circular definition, [16] time in physics is operationally defined as "what a clock reads", specifically a count of repeating events such as the SI second. [6] [17] [18] Although this aids in practical measurements, it does not address the essence ...

  5. Frequency - Wikipedia

    en.wikipedia.org/wiki/Frequency

    The period (symbol T) is the interval of time between events, so the period is the reciprocal of the frequency: T = 1/f. [ 2 ] Frequency is an important parameter used in science and engineering to specify the rate of oscillatory and vibratory phenomena, such as mechanical vibrations, audio signals ( sound ), radio waves , and light .

  6. Orders of magnitude (time) - Wikipedia

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

    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 4–16 μs: The time needed to execute one machine cycle by a 1960s minicomputer: 10 −3: millisecond: ms One ...

  7. Jiffy (time) - Wikipedia

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

    In astrophysics and quantum physics a jiffy is, as defined by Edward R. Harrison, [13] the time it takes for light to travel one fermi, which is approximately the size of a nucleon. One fermi is 10 −15 m , so a jiffy is about 3 × 10 −24 s .

  8. Phase (waves) - Wikipedia

    en.wikipedia.org/wiki/Phase_(waves)

    When two signals with these waveforms, same period, and opposite phases are added together, the sum + is either identically zero, or is a sinusoidal signal with the same period and phase, whose amplitude is the difference of the original amplitudes. The phase shift of the co-sine function relative to the sine function is +90°.

  9. Imaginary time - Wikipedia

    en.wikipedia.org/wiki/Imaginary_time

    Imaginary time is a mathematical representation of time that appears in some approaches to special relativity and quantum mechanics. It finds uses in certain cosmological theories. Mathematically, imaginary time is real time which has undergone a Wick rotation so that its coordinates are multiplied by the imaginary unit i .