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heman
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how to measure speed of light??
http://www.what-is-the-speed-of-light.com/The speed of light in vacuum is exactly 299,792,458 m/s (metres per second)
In 1983 the SI (Systeme International) defined a metre as:
The metre is the length of the path traveled by light in vacuum during a time interval of 1/299 792 458 of a second.
When people refer to the speed of light, they refer to the definition above - the speed of light in a vacuum.
The speed of light is normally rounded to 300 000 kilometers per second or 186 000 miles per second.
The speed of light depends on the material that the light moves through - for example: light moves slower in water, glass and through the atmosphere than in a vacuum. The ratio whereby light is slowed down is called the refractive index of that medium.
In general, the difference in the speed of light in other mediums is ignored.
dyknowsore said:My favorite speed of light measurment was earlier though. Consisted of two guys with lanterns on different hill tops. One of them would uncover his lantern and the other would uncover his as soon as he saw the first one. Their value for the speed of light? "Extremely fast"
(Wish I could remember who they were.)
dyknowsore said:My favorite speed of light measurment was earlier though. Consisted of two guys with lanterns on different hill tops. One of them would uncover his lantern and the other would uncover his as soon as he saw the first one. Their value for the speed of light? "Extremely fast"
(Wish I could remember who they were.)
The speed of light is defined as the speed at which light travels in a vacuum, which is approximately 299,792,458 meters per second. It is important to measure because it is a fundamental constant in physics and plays a crucial role in understanding the behavior of the universe.
The most common method for measuring the speed of light is through the use of the Michelson-Morley experiment, which involves measuring the time it takes for light to travel between two points. Other methods include using lasers and mirrors, and using the frequency and wavelength of light.
The current accepted value for the speed of light is based on the most recent measurements, which have an uncertainty of less than 0.0000000001%. This level of accuracy has been achieved through advancements in technology and the use of multiple measurement methods.
According to the theory of relativity, the speed of light has always been constant. However, there have been some proposed theories that suggest the speed of light may have varied in the distant past. This is still a topic of debate and further research is needed.
The speed of light is a crucial factor in many modern technologies, such as telecommunications, GPS, and medical imaging. It also plays a role in our understanding of the universe and has helped scientists make significant discoveries about the nature of light, space, and time.