At present, the speed of light is captured in space
(2.9979 * 10 ^ 8) meters (m) / second (s).
Many people have experimented with measuring the speed of light.
Galileo first performed this experiment in 1830. He and his associates covered 1.5 km. Stand with a lamp on the top of two hills in the distance. The condition is that when one light is on, the other will also turn on the light immediately. Thus, after lighting a lamp, he notices how long he sees the light on the other end and finds out that the speed of light is 0.000000 km/sec. But since there has never been such a small time-measuring clock so long ago, he said, "the speed of light is much higher."
Then, in 18, another experiment was carried out by the Danish physicist Ole Rømer. He observed the motion of Jupiter and one of its moons, IO, with a telescope and reported that it took 22 minutes for light to travel a distance equal to the diameter of the Earth. If he had known the diameter of the earth at that time, he might have found out the speed of light (2.27 * 10 ^ 8) m / s which is unusable.
In 1849, the French physicist Armand Hippolyte Louis Fizeau gave the best result of that time. He used a wheel with 620 teeth of equal thickness and 620 gaps. The mirror leaning in front of it and exactly 16 km behind. Put another mirror in the distance and let the light enter through the front mirror. The light is reflected by the mirror and enters at a speed of 13 km at a rev of 13 rev/sec. Reflected in a distant mirror, it would get stuck in the teeth of the wheel again without coming out through the small gap of the disc. Then he could not see any light from the front. Thus,
It takes time to cross the length of 1 tooth {1 / (13 * 720 * 2) 6 seconds = light travels 18000 meters {16000 / c c seconds.
From here Fizaeu C = 3.13 * 10 ^ 8 m / s. Give an account that is very acceptable.
In 182 Léon Foucaul used a rotating mirror to calculate (2.96 * 10 ^ 8 m / s) where there was an error up to (+, - 500). From 18 to 1931, Albert Abraham Micheson (the same Michelson-Morrell gentleman in Inter's physics book) refined Foucaul's theory and used a better rotating mirror to illuminate St. Los Angeles. Get the more perfect speed of light by traveling from Mount to Mount San Antonio, California (2.99697 * 10 ^ 8 m / s) where the error value is only (+, - 50).
After Maxwell's wave theory was published, the path to determining the speed of light became easier. In 1958, a British scientist (still alive) used the #Keith_Davy_Froome microwave interferometer to obtain a value (2.996925 * 10 ^ 8 m / s) that showed only (+, - 0.1) error.
Scientists Lord Kelvin (189) and Isidor Rabi (1945) developed the concept of the Atomic Clock and later refined laser technology of the 1960s. Kabir's first successful test takers were KM Evenson and others. Basically, the emitted laser beam is reflected in a mirror and recorded once it is read in the Atomic Clock. Thus the speed of light is monitored by measuring the total travel distance and time delay of each beam. The result obtained by Evenson was (2.997924574 * 10 ^ 8 m / s), error only (+, - 0.001).
Atomic Clock adheres to Einstein's theory of relativity where if 1 microsecond is incorrect, the average will be about 300 meters. Einstein and Newton have done many experiments to measure the speed of light, but their experiments have not received much recognition based on contemporary results. Modern GPS also uses an Atomic Clock which gives almost 100% accurate speed of light.
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