If this case could ever happen, the speed would follow from this formula:

with f the frequency and lambda the wavelength. We are give a wavelength of 10m. The frequencies of the visible light can range between 400 to about 790 Terahertz, so let us pick a middle point of 600 THz ("green-ish") as a "representative."

The speed of such a wave would have to be 6e+15 m/s (which would be 7 orders of magnitude higher than the universal speed of light constant)
Let's calculate the average acceleration. It is the rate of changing speeds. Hence, we need to calculate the difference of speeds. 10-6=4 m/s. The rate is now

.
In general, the formula for the mean acceleration between two times 1 and 2 is given by:

where v1 and v2 are the speeds at the respective points and T is the time interval between them.
The <em>gaseous state</em> of matter does that. A gas expands to take the shape and volume of whatever you put it into.
I try to aim a the right key or do typing lessons
Answer:
By observing the color of lines in the spectrum.
Explanation:
There are two types of lines in the spectrum explained below:
i) Bright lines: Bright lines occurs on the spectrum when atoms emit photons. These bright lines show the emission line spectrum.
ii) Dark Lines: Dark lines occurs on the spectrum when atoms absorb photons. These black lines show the absorption line spectrum.
Hence, by observing the color of lines it is possible to identify emission line spectrum and absorption line spectrum.