Just now, in 2009, the figure considered to be the most accurate estimate of the speed of light in free space is 299,792,458 meters per second (186,282 miles per second).
2 (no units)
C represents the speed of light. In a vacuum it is 299,792,458 meters per second. C is also the maximum speed at which anything in the universe can travel.
The speed of light in fused quartz is lower than in vacuum, so the frequency of light will remain the same as in vacuum even though the wavelength is shorter. The frequency is determined by the source and the medium does not affect it.
Both visible light and gamma rays travel at the speed of light in a vacuum, which is approximately 299,792 kilometers per second (or about 186,282 miles per second). Thus, there is no difference in the speed at which visible light and gamma rays travel.
Average distance from the earth to the sun = 1.496*1011 metres. Speed of light in vacuum = 3.0*108 metres per xecond.
To convert frequency to wavelength, you can use the formula: wavelength = speed of light / frequency. The speed of light in a vacuum is approximately 3.00 x 10^8 meters per second. Dividing this speed by the frequency in hertz will give you the corresponding wavelength in meters.
it depends on the medium the light is travelling through. In a vacuum, light travels ~299,000km/s. In air, light travels ~298,000km/s. And in water light travels ~225,000km/s. Essentially you take the speed of light in a vacuum and divide by the refractive index of the material the light is passing through, this will give you the new speed of light in that medium. As for the importance in astronomy, I am not sure, but I will guess that it has to do with light refracting as it enters the earth's atmosphere ever so slightly. this may throw off measurements a bit or result in slight corrections in telescopic direction and focus. Other than that I am not sure as I have never heard of this being an issue.
Radiant heat travels at the speed of light in a vacuum, which is approximately 186,282 miles per second (299,792 kilometers per second). This means that heat energy is transmitted quickly through radiation in space.
The speed of light is not always fixed at 299792458 m/s. In earth's atmosphere, the speed of light slows, though this is negligible. In water, light travels at 75% of c, and in a diamond, light travels at .40 c. C is the speed of light, rounded to 300,000 km/s.
Light travels at 300,000 kps in air. Glass is a more dense medium than air. This means that the particles in glass are more than compared to air. Because of this, light will slow down, thus will bend towards the line of equilibrium (which is a fancy word for line of the center). This makes the light face another angle inside the glass and when it passes out of the glass. And WHY does light slow down in glass? As stated above, there are more particles in glass than in air. Imagine of you were to pass though a crowd. Wouldn't it be faster to pass through a crowd with less people instead of a crowd with a lot of people pushing you here and there?The speed of light in glass is 65.99% of the speed of light in vacuum.That is 65.99/100 x 3 x 108 ms-1While it's in the glass, nothing happens to the speed.The speed of light in most substances - such as glass - is less than the speed of light in a vacuum. Specifically, the speed of light in glass is also less than the speed of light in air. The speed of light in air is almost the same as the speed of light in a vacuum. (One rule of thumb is that the speed of light tends to be slower in more dense materials ... this isn't always true, but for "similar" materials like different kinds of silicate glasses there's a fairly strong correlation between refractive index, which is related to the speed of light in that material, and density).
The speed of light, in vacuum, is exactly 299,792,458 metres per second or 299,792.458 kilometres per second. The values are exact because this is how a metre is defined. The relationship between a kilometre and a mile is not exact, so it is not possible to give an exact figure for the speed in miles. It is approximately 186,282 miles per second.
The speed of light (and all other forms of electromagnetic radiation) in vacuum is determined bythe electrostatic permittivity (ε0) and magnetic permeability (μ0) of free space.An interesting thought ... we have no way of knowing whether these physical constants are the samenumbers today that they have always been. If either of them has changed since the birth of the universe,then the speed of light changed, and our observations of the earliest cosmos give an erroneous numberfor the age of the universe.But anyway, that's what these quantities are today, and they're what determines the speed of light,as is so neatly predicted by Maxwell's equations and verified spot-on by the best measurements.