Question

The ratio of amplitude of electric field to the amplitude of the magnetic field associated with an electromagnetic wave propagating in glass (n = 1.5) is ______.

Options

• 3 × 10⁸ ms⁻¹

• 2 × 10⁸ ms⁻¹

• 3.3 × 10⁻⁹ ms⁻¹

• 5 × 10⁻⁹ ms⁻¹

Answer 1

The ratio of amplitude of electric field to the amplitude of the magnetic field associated with an electromagnetic wave propagating in glass (n = 1.5) is 2 × 10⁸ ms⁻¹.

Explanation:

For an electromagnetic wave, the ratio of the amplitude of the electric field (E₀) to the amplitude of the magnetic field (B₀) is equal to the speed of the wave in that medium (v).

`E_0/B_0 = v = c/n`

Where c is the speed of light in vacuum (3 × 10⁸ m/s), and n is the refractive index of the medium.

Given: n = 1.5 and c = 3 × 10⁸ m/s.

The speed of light in glass is:

v = `(3 xx 10^8)/1.5`

= 2 × 10⁸ ms⁻¹

Thus, the ratio `E_0/B_0` = 2 × 10⁸ ms⁻¹.