Search results
Results from the WOW.Com Content Network
Orders of magnitude (time) An order of magnitude of time is usually a decimal prefix or decimal order-of-magnitude quantity together with a base unit of time, like a microsecond or a million years. In some cases, the order of magnitude may be implied (usually 1), like a "second" or "year". In other cases, the quantity name implies the base unit ...
Unit of time. A unit of time is any particular time interval, used as a standard way of measuring or expressing duration. The base unit of time in the International System of Units (SI), and by extension most of the Western world, is the second, defined as about 9 billion oscillations of the caesium atom. The exact modern SI definition is ...
This is a list of radioactive nuclides (sometimes also called isotopes), ordered by half-life from shortest to longest, in seconds, minutes, hours, days and years. Current methods make it difficult to measure half-lives between approximately 10 −19 and 10 −10 seconds.
10−18 s. An attosecond (abbreviated as as) is a unit of time in the International System of Units (SI) equal to 10 −18 or 1 ⁄ 1 000 000 000 000 000 000 (one quintillion) of a second. [1] An attosecond is to a second, as a second is to approximately 31.69 billion years. [2]
SI units. A femtosecond is a unit of time in the International System of Units (SI) equal to 10 −15 or 1⁄1 000 000 000 000 000 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. For context, a ray of light travels ...
Doomsday Clock. The Doomsday Clock is a symbol that represents the likelihood of a human-made global catastrophe, in the opinion of the members of the Bulletin of the Atomic Scientists. [1] Maintained since 1947, the Clock is a metaphor, not a prediction, for threats to humanity from unchecked scientific and technological advances.
Counts per minute (abbreviated to cpm) is a measure of the detection rate of ionization events per minute. Counts are only manifested in the reading of the measuring instrument, and are not an absolute measure of the strength of the source of radiation. Whilst an instrument will display a rate of cpm, it does not have to detect counts for one ...
Time constant. In physics and engineering, the time constant, usually denoted by the Greek letter τ (tau), is the parameter characterizing the response to a step input of a first-order, linear time-invariant (LTI) system. [ 1 ][ note 1 ] The time constant is the main characteristic unit of a first-order LTI system. It gives speed of the response.