Question

The speed of plane electromagnetic waves is maximum in ______.

Options

• glass

• vaccum

• tourmaline

• water

Answer 1

The speed of plane electromagnetic waves is maximum in vaccum.

Explanation:

`v = 1/(sqrt(mu_0 mu_tau∈_"o"∈_"r")) = "c"/sqrt(∈_"r"mu_"r")`

Since, `∈_"r"mu_"r"` > 1,

Thus, c (speed of light in vacuum) > v (speed of light in any other medium)

Hence it is maximum in a vacuum.