What is speed of light ?

Question

what is the speed of dark Then?

Answer 1

299,792,458 metres per second (1,079,252,849 km/h).

I think its equal to going around the earth 7 times in 1 second.

Answer 2

light-300000000

dark-000000000

Answer 3

The speed of light in the vacuum of free space is an important physical constant usually denoted by the letter c. It is the speed of all electromagnetic radiation, including visible light, in free space. It is the speed of anything having zero rest mass. In metric units, the speed of light in vacuum is defined to be exactly 299,792,458 metres per second (1,079,252,849 km/h). The speed of light can be assigned a definite numerical value because the fundamental SI unit of length, the metre, has been defined since October 21, 1983, as the distance light travels in a vacuum in 1/299,792,458 of a second; in other words, any increase in the measurement precision of the speed of light would refine the definition of the metre, but not alter the numerical value of c. The approximate value of 3×108 m/s is commonly used in rough estimates (the error is 0.07%). In imperial units, the speed of light is about 670,616,630.6 miles per hour or 983,571,056 feet per second, which is about 186,282.397 miles per second, or roughly one foot per nanosecond. See also the later section of this article at "Speed of light set by definition".

The speed of light when it passes through a transparent or translucent material medium, like glass or air, is less than its speed in a vacuum. The ratio of the speed of light in the vacuum to the observed phase velocity is called the refractive index of the medium. See dispersion (optics). In general relativity c remains an important constant of spacetime, however the concepts of 'distance', 'time', and therefore 'speed' are not always unambiguously defined due to the curvature of spacetime caused by gravitation. When measured locally, light in a vacuum always passes an observer at c.

Answer 4

3 x 10*8 m/s

Answer 5

300000000 m/s

Answer 6

speed of light= 299 792 458 m / s

speed of dark = http://www.freakface.com/speedofdark/

Answer 7

9.3 * 10.......................15 times kms

Answer 8

The speed of light is slowing down according to what I have read. Not by much, but as I recall it has slowed by just over a second in the last 200 years. This may not seem significant to us, but it is as far as the universe is concerned.

the other answers are correct not taking the slowing into account.

Answer 9

3 x 10^8 m/s

dont know.

Answer 10

The speed of dark is just light leaving an area. So the speed of dark is the same as the speed of light.

Answer 11

lol, i had the same question in phy test:D its 3x10^8...

Answer 12

The speed of light in the vacuum of free space is an important physical constant usually denoted by the letter c.[1] It is the speed of all electromagnetic radiation, including visible light, in free space. It is the speed of anything having zero rest mass[2]. In metric units, the speed of light in vacuum is defined to be exactly 299,792,458 metres per second (1,079,252,849 km/h).[3] The speed of light can be assigned a definite numerical value because the fundamental SI unit of length, the metre, has been defined since October 21, 1983, as the distance light travels in a vacuum in 1/299,792,458 of a second; in other words, any increase in the measurement precision of the speed of light would refine the definition of the metre, but not alter the numerical value of c. The approximate value of 3×108 m/s is commonly used in rough estimates (the error is 0.07%). In imperial units, the speed of light is about 670,616,630.6 miles per hour or 983,571,056 feet per second, which is about 186,282.397 miles per second, or roughly one foot per nanosecond. See also the later section of this article at "Speed of light set by definition".

The speed of light when it passes through a transparent or translucent material medium, like glass or air, is less than its speed in a vacuum. The ratio of the speed of light in the vacuum to the observed phase velocity is called the refractive index of the medium. See dispersion (optics). In general relativity c remains an important constant of spacetime, however the concepts of 'distance', 'time', and therefore 'speed' are not always unambiguously defined due to the curvature of spacetime caused by gravitation. When measured locally, light in a vacuum always passes an observer at c.

Dark is merely the absence of light, so it has no speed.

Answer 13

the speed of light is 3*10^8 m/s.

dark doesn't travel. it spreads.

Answer 14

1,86,000 miles per second.

Answer 15

1,079,252,849 km/h

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Answer 16

In metric units, the speed of light in vacuum is defined to be exactly 299,792,458 metres per second

About darkness... theoretically there is nothing called darkness. Actually light is only a part of the visible spectrum from violet to red. Above violet (means ultra violet and above) and below red (means infra red and below) are invisible waves which are not visible by human beings. Those may be visible by some other species and by some instruments. So darkness itself is light not visible to us. So has the same velocity as light

Answer 17

670,616,630.6 miles per hour

Answer 18

3 x 10^8 m/s