10 items with this tag.
C1-3 A measurement device for time which uses the energy difference between the two lowest energy states of the cesium atom, which, when bombarded by microwaves of the correct electromagnetic spectrum, frequency of light undergo a state change from one to the other.
C1-3 Discussion of Units Since 1967 the standard unit for time is the second, and its operational definition is based on the atomic clock.
C1-3 A physical quantities Discussion of Units The kilogram is defined to be the mass of a particular cylinder of platinum-iridium alloy kept near Paris.
C1-3 A physical quantities that is a scalar quantity Discussion of Units In 1983, the speed of light was defined to be $299,792,458 \ \text{m/s}$ and meters are defined to be the length that electromagnetic waves and light travels in $1 / 299,792,458 \ \text{s}$ in a vacuum.
C1-3 Definition Based on an atomic clock.
C1-3 Definition When measuring physical quantities, this is always used. SI units is has been used since the 1960s.
C1-3 Discussion In 1983, the speed of light was defined to be $299,792,458 \ \text{m/s}$ and meters are defined to be the length that electromagnetic waves and light travels in $1 / 299,792,458 \ \text{s}$ in a vacuum.
C1-3 Discussion of Units The kilogram is defined to be the mass of a particular cylinder of platinum-iridium alloy kept near Paris.
C1-3 Definition physical quantities which can only be described in terms of the experiment or measurement that provides their result, such as: measuring distance using a ruler measuring duration using a stopwatch Canonical Hub: CANONICAL_INDEX.
C1-3 KeyConcept Definition Any number used to describe a phenomena of nature quantitatively.