The dielectric constant of air is 1.006. The speed of electromagnetic wave travelling in air is `axx10^(8)ms^(-1)`, where a is about

Options

A. 3
B. 3.88
C. 2.5
D. 3.2

Answer

A

Explanation

For an electromagnetic wave (in vacuum),
Velocity `C=(1)/(sqrt(mu_(0)epsilon_(0)))=3xx10^(8)ms^(-1)`
Air acts almost as vacuum, hence
`a=3` (approx)