What is the speed of light and how do you work it out ?

Answer 1

The speed of light is roughly 186,262 mph. You can either measure it directly or you can compute it from a set of equations that predict electromagnetic radiation called Maxwell's equations. The speed of light is derived from two physical constants in the equations

Answer 2

they don't once something is measured that is unchanging it becomes a factor in calculations but doesn't need to be measured - as for how they did - long and complicated but here is a bit of it

Starting with Roemer's 1676 breakthrough endeavors, the speed of light has been measured at least 163 times utilizing a wide variety of different techniques by more than 100 investigators (see Table 1 for a compilation of methods, investigators, and dates). As scientific methods and devices were refined, the error limits of the estimates narrowed, although the speed of light has not significantly changed since Roemer's seventeenth century calculations. Finally in 1983, more than 300 years after the first serious measurement attempt, the speed of light was defined as being 299,792.458 kilometers per second by the Seventeenth General Congress on Weights and Measures. Thus, the meter is defined as the distance light travels through a vacuum during a time interval of 1/299,792,458 seconds. In general, however, (even in many scientific calculations) the speed of light is rounded to 300,000 kilometers (or 186,000 miles) per second. Arriving at a standard value for the speed of light was important for establishing an international system of units that would enable scientists from around the world to compare their data and calculations.

Answer 3

You work it out by shining a light in a short pulse. A detector next to the light will show a pulse as the light leaves. Then you have a mirror some distance away that bounces the light back. You will then see another pulse somewhat later. The distance between the detector and the mirror (there and back) divided by time between the two pulses will be the speed.

Answer 4

The speed of light in a vacuum is equal to the value c, which is 299,792,458 m/s. A good approximation is 3x10^8 m/s.

This is either measured directly or predicted by dividing the electric constant by the magnetic constant. This also proves that light is an electromagnetic wave.

Answer 5

The speed of light is 186,000 miles per second or 300,000 kilometers per second.

You'll need someone smarter than me to tell you how they worked it out. I have an idea, I'd be able to understand it if it were explained to me but I can't put it into words at the minute.

Answer 6

3.00 x 10^8 m/s. this is why the light from the sun takes 8 minutes, 20 seconds to travel the ~93 million miles to reach earth

Answer 7

3*10^8 m/s

Answer 8

In answer to your question "what is the speed of light", it is the speed at which light travels of course. which is nearly as fast as my volkswagen golf gti.

Answer 9

3x10^8 meters per second. Look up the Michaelson-Morley experiment. But actually, it's not measured, it's defined.

Answer 10

186,000 miles per second.

No idea how they work it out, though.