Einstein’s theory of relativity is founded on the **speed of light being constant**. However, there are postings and scientific discussions where there is mention of “**light slowing down traveling through materials”**. Does it really slow down in the material or is the entrance/exit delay explained by something else?
For example, would it instead be explained that the photons are absorbed and then re-generated on the other side of atoms as they make their way through water, glass, etc? The “delay” is then actually a measure of the time spent between absorption and emission?
In: 6
Yes, the propagation velocity changes based on the dielectric constant of the material. For fiberglass (FR4 to be specific) circuit boards, which make up 99% of what goes in electronics, the propagation velocity is roughly half the normal speed of light.
Certain ceramic materials can have even higher dielectric constants (in the tens and hundreds), which allow antennas to be much smaller.
Latest Answers