Question

Speed of the light.

Answer 1

Hint: In a vacuum, the speed of light, c, is \[3 \times {10^9}m{s^{ - 1}}\] . When light travels through a clear substance, it travels at the speed of c between the atoms. However, each interaction with charged particles in the medium causes the phase of the light to be delayed, reducing the speed of the light within the medium, \[v\] . The refractive index of the medium is defined as the ratio of the speed of light in vacuum to the speed of light in the medium, indicated by \[n\] : $n = \dfrac{c}{v}$

Complete step-by-step solution:
The speed at which light waves propagate through various materials is referred to as the speed of light. In particular, the speed of light in a vacuum has now been determined to be \[299,792,458\]metres per second.
The speed of light is regarded as a fundamental natural constant. Its significance extends far beyond its role in characterising an electromagnetic wave characteristic. It is the universe's sole limiting velocity, serving as an upper constraint on signal transmission speeds as well as the speeds of all material particles. The speed of light \[\left( c \right)\] serves as a proportionality constant in the famous relativity equation \[E = m{c^2}\] , connecting the previously independent ideas of mass \[\left( m \right)\] and energy\[\left( E \right)\] .

Note:The concept of "speed" does not exist physically beyond the speed of light since it requires measuring a specific amount of distance travelled in space over a specific length of time. The expression "faster than light" is, in fact, worthless in terms of physics. It's the same thing as saying "darker than black."