speed light
121Faster-than-light — (also superluminal or FTL) communications and travel refer to the propagation of information or matter faster than the speed of light. Science fiction style space travel, dubbed true FTL, defies known physics.Under the special theory of… …
122One-way speed of light — The one way speed of light from a source to a detector, cannot be measured independently of a convention as to how to synchronize the clocks at the source and the detector. What can however be experimentally measured is the round trip speed (or… …
123Film speed — is the measure of a photographic film s sensitivity to light, determined by sensitometry and measured on various numerical scales, the most recent being the ISO system. A closely related ISO system is used to measure the sensitivity of digital… …
124Variable speed of light — The variable speed of light (VSL) concept states that the speed of light in a vacuum, usually denoted by c , may not be constant in some cases. In most situations in condensed matter physics when light is traveling through a medium, it… …
125Slow light — is the literal slowing of the speed of light. It is the propagation of an optical pulse or other modulation of an optical carrier at a very low group velocity. The term is usually only applied when the velocity is at least hundreds of times… …
126Road speed limit enforcement in Australia — constitutes the actions taken by the authorities to force road users to comply with the speed limits in force on Australia s roads. Speed limit enforcement equipment such as speed cameras and other technologies such as radar and LIDAR are widely… …
127Shutter speed — [ aperture size to achieve proper exposure.] In photography, shutter speed is the length of time a shutter is open; the total exposure is proportional to this exposure time, or duration of light reaching the film or image… …
128Traffic light — The traffic light, also known as traffic signal, stop light, traffic lamp, stop and go lights, robot or semaphore, is a signaling device positioned at a road intersection, pedestrian crossing, or other location. Its purpose is to indicate, using… …
