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A picosecond (abbreviated as ps) is a unit of time in the International System of Units (SI) equal to 10 −12 or (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 31,689 years.
A nanosecond ( ns) is a unit of time in the International System of Units (SI) equal to one billionth of a second, that is, of a second, or 10 −9 seconds. The term combines the SI prefix nano- indicating a 1 billionth submultiple of an SI unit (e.g. nanogram, nanometre, etc.) and second, the primary unit of time in the SI.
Attosecond physics, also known as attophysics, or more generally attosecond science, is a branch of physics that deals with light-matter interaction phenomena wherein attosecond (10 −18 s) photon pulses are used to unravel dynamical processes in matter with unprecedented time resolution.
Chinese numerals are words and characters used to denote numbers in written Chinese . Today, speakers of Chinese languages use three written numeral systems: the system of Arabic numerals used worldwide, and two indigenous systems. The more familiar indigenous system is based on Chinese characters that correspond to numerals in the spoken language.
The speed of sound is the distance travelled per unit of time by a sound wave as it propagates through an elastic medium. At 20 °C (68 °F), the speed of sound in air is about 343 m/s (1,125 ft/s; 1,235 km/h; 767 mph; 667 kn ), or one km in 2.91 s or one mile in 4.69 s. It depends strongly on temperature as well as the medium through which a ...
A millisecond (from milli- and second; symbol: ms) is a unit of time in the International System of Units equal to one thousandth (0.001 or 10 −3 or 1 / 1000) of a second [1] [2] and to 1000 microseconds . A unit of 10 milliseconds may be called a centisecond, and one of 100 milliseconds a decisecond, but these names are rarely used. [3] .
Numerical value, notation, and units The speed of light in vacuum is usually denoted by a lowercase c, for "constant" or the Latin celeritas (meaning 'swiftness, celerity'). In 1856, Wilhelm Eduard Weber and Rudolf Kohlrausch had used c for a different constant that was later shown to equal √ 2 times the speed of light in vacuum. . Historically, the symbol V was used as an alternative symbol ...
