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A Morse code light is light in which appearances of light of two clearly different durations (dots and dashes) are grouped to represent a character or characters in the Morse Code. For example, "Mo(A)" is a light in which in each period light is shown for a short period (dot) followed by a long period (dash), the Morse Code for "A".
Either a quick or a very quick sequence of light flashes may be used; the choice allows for two similar nearby marks to be uniquely identified by their lights. A cardinal mark may be used to accomplish the following: Indicate that the deepest water is an area on the named side of the mark; Indicate the safe side on which to pass a danger
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. It has also more informally been defined as "one light-foot", which is equal to approximately one ...
Words with specific British English meanings that have different meanings in American and/or additional meanings common to both languages (e.g. pants, cot) are to be found at List of words having different meanings in American and British English. When such words are herein used or referenced, they are marked with the flag [DM] (different meaning).
A quick-start ballast eliminates the need for a starter switch, a common source of lamp failures. Nonetheless, Quick-start ballasts are also used in domestic (residential) installations because of the desirable feature that a Quick-start ballast light turns on nearly immediately after power is applied (when a switch is turned on).
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Light: When quicklime is heated to 2,400 °C (4,350 °F), it emits an intense glow. This form of illumination is known as a limelight, and was used broadly in theatrical productions before the invention of electric lighting. [14] Cement: Calcium oxide is a key ingredient for the process of making cement. As a cheap and widely available alkali.
Beam of sun light inside the cavity of Rocca ill'Abissu at Fondachelli-Fantina, Sicily. The speed of light in vacuum is defined to be exactly 299 792 458 m/s (approximately 186,282 miles per second). The fixed value of the speed of light in SI units results from the fact that the metre is now defined in terms of the speed of light.