Question

What happens to the speed of an electromagnetic wave as it travels through a vacuum?

Answer 1

It goes to a constant value called c, which is 300000000m/s
\[3.0 \times 10^8 \frac{ m }{ s }\]
same as speed of light.

Answer 2

constant speed c.which is equal to 2.9979246*10^8 m/s. this is from c=1/root of mu*epsilon

Answer 3

Exact value is 299792458 m/s