299 792.458 km s-1.
This is not an approximate figure - it is exactly right by definition.
If there was a tiny error it will be corrected by adjusting the meter !
The speed of light in a vacuum is 186,282.397 miles per second or 670,616,629.2 miles per hour.
The speed of light is not limited in a vacuum - the speed of light is fastest in a vacuum. But that is what Einstein called the "Cosmic Speed Limit" - nothing can move faster than the speed of light in a vacuum, or even quite asfast.
About 2/3 its speed in a vacuum.
The speed of light is 186,000 miles per second in a vacuum.
In a vacuum the speed of red and blue light are the same as all light, 300,000,000m/s. Their frequency and wavelength will be different but the speed remains the same.
The speed of light in a vacuum is approximately 299,792 kilometers per second.
The speed of light is constant in a vacuum and does not change. It travels at approximately 299,792 kilometers per second in a vacuum.
Light travels at a speed of approximately 299,792 kilometers per second in a vacuum.
The speed of light is constant and is approximately 299,792 kilometers per second in a vacuum.
The speed of light in a vacuum is approximately 299,792 kilometers per second.
Light of different colors in a vacuum all travel at the same speed, which is approximately 299,792 kilometers per second.
The speed of light is equal to 1 unit of c, where c is the speed of light in a vacuum, approximately 299,792 kilometers per second.
The speed of light in a vacuum is approximately 299,792 kilometers per second.
The fastest possible speed that an object can travel in a vacuum is the speed of light, which is approximately 299,792 kilometers per second.
In a vacuum, all light waves travel at the same speed, which is approximately 299,792 kilometers per second.
The speed of a gamma particle is approximately the speed of light, which is around 299,792 kilometers per second in a vacuum.
All colors of light travel at the speed of light in a vacuum, which is approximately 299,792 kilometers per second (186,282 miles per second). This speed is a constant in a vacuum for all wavelengths of light.