Question

The speed of light in vacuum is equal to
$A.{{\mu }_{o}}{{\varepsilon }_{o}}$
$B.\mu _{o}^{2}\varepsilon _{o}^{2}$
$C.\sqrt{{{\mu }_{o}}{{\varepsilon }_{o}}}$
$D.\dfrac{1}{{{\mu }_{o}}{{\varepsilon }_{o}}}$
$E.\dfrac{1}{\sqrt{{{\mu }_{o}}{{\varepsilon }_{o}}}}$

Answer 1

Hint: We know that light is a non-mechanical wave, which can travel in a vacuum also without any need for a medium. It is also very much known that light travels faster in vacuum or air than any medium. Despite having particle nature light travels as an electromagnetic wave.

Complete step-by-step solution
Propagation of light is defined as the manner in which light travels from one point to another. The propagation of light is associated with the transfer of energy from one point to another.
The speed of light in vacuum is equal to $3\times {{10}^{8}}m{{s}^{-1}}$ . speed of light is given with the following formula:-
$c=\dfrac{1}{\sqrt{{{\mu }_{o}}{{\varepsilon }_{o}}}}$. Where $c$ denotes the speed of light in vacuum or air, ${{\mu }_{o}}$ is permeability of vacuum and ${{\varepsilon }_{o}}$ is the permittivity of vacuum or air.
When light travels in a vacuum there is no scattering occurring, therefore the beam of light is invisible in a vacuum.
Additional Information:
We should also know something about permeability and permittivity.
Permeability of any material or medium is defined as the measure of a material or medium to allow the formation of magnetic fields within. It is denoted by the letter $\mu $. SI unit of permeability is henry per meter.
The permittivity of the material or medium is defined as the measure of the resistance offered against the formation of electric fields. It is denoted by the letter $\varepsilon $. SI unit of permittivity is farad per meter.

Note: We should not be confused over the fact that permeability and permittivity are two different terms with different meanings. The propagation of light depends on the medium and hence, has different velocities in different media. It should also be noted that permeability and permittivity are also medium dependent.