The ratio of the amplitude of a magnetic field to the amplitude of an electric field for an electromagnetic wave propagating in a vacuum is equal to:

1.	reciprocal of speed of light in vacuum.
2.	the ratio of magnetic permeability to the electric susceptibility of vacuum.
3.	unity.
4.	the speed of light in a vacuum.

The magnetic field in a plane electromagnetic wave is given by:
\(B_y = 2\times10^{-7} ~\text{sin}\left(\pi \times10^{3}x+3\pi\times10^{11}t\right )\text{T}\)${}_{}$
The wavelength is:
1. \(\pi\times 10^{3}~\text{m}\)
2. \(2\times10^{-3}~\text{m}\)
3. \(2\times10^{3}~\text{m}\)
4. \(\pi\times 10^{-3}~\text{m}\)

Which of the following is not an electromagnetic wave?

1. Radio wave

2. Micro wave

3. Cosmic rays

4. $\mathrm{\gamma }$-rays

If an electromagnetic wave propagating through vacuum is described by \(E_y= E_0 \sin(kx-\omega t); ~B_z= B_0\sin(kx-\omega t),\) then:
1. \(E_0k=B_0\omega\)
2. \(E_0B_0 = \omega k\)
3. \(E_0\omega= B_0k\)
4. \(E_0B_0= \frac{\omega}{k}\)

A compass needle is placed in the gap of a parallel plate capacitor. The capacitor is connected to a battery through a resistance. The compass needle:

A plane electromagnetic wave is incident on a material surface. The wave delivers momentum \(p\) and energy \(E.\) Then:

Displacement current goes through the gap between the plates of a capacitor when the charge of the capacitor:

About \(5\)% of the power of a \(100\) W light bulb is converted to visible radiation. What is the average intensity of visible radiation at a distance of \(1\) m from the bulb?

1. \(0.472\) W/m²
2. \(0.398\) W/m²
3. \(0.323\) W/m²
4. \(0.401\) W/m²