An electromagnetic wave going through Vaccum is described by

$E=E_0\sin (kx-\omega t)$
$B=B_0\sin (kx-\omega t)$

(1) $E_0{B}_0=\omega k$

(2) $E_0\omega =B_{0}k$

(3) $E_{0}k=B_0\omega$

(4) none of these

 

The ratio of $\frac{E_0}{H_0}$ for a plane electromagnetic wave has the dimension of

(1) Impedance

(2) Resistance

(3) Both 

(4) None

A plane E M wave of frequency 25 MHz travels in free space in the x-direction. At a particular point in space and time $E=6.3 \hat{j} V/m$ then B at the point is 

(1) $2.1\times {10}^{-8} -\hat{k}$

(2) $2.1\times {10}^{-8} \hat{k}$

(3) 2.1 $\hat{k}$

(4) $2.1\times {10}^{-8} \hat{i}$

In an electromagnetic wave, the amplitude of the electric field is \(1~\text{V/m}.\) The frequency of a wave is \(5\times 10^{14}~\text{Hz}.\) The wave is propagating along the \(z\text-\)axis. The average energy density of the electric field in \(\text{J/m}^3,\) will be:
1. \(2.2\times 10^{-12}\)
2. \(4.4\times 10^{-12}\)
3. \(6.6\times 10^{-12}\)
4. \(8.8\times 10^{-12}\)

The infra-red spectrum lies between :

(1) radio wave and microwave region

(2) the micro-wave and visible region

(3) the visible and ultraviolet region

(4) the ultraviolet and the X-ray region

Which of the following electromagnetic waves has minimum frequency?
1. Radio waves
2. Infrared waves
3. Microwaves
4. X-rays

A lamp emits monochromatic green light uniformly in all directions. The lamp is \(3\%\) efficient in converting electrical power to electromagnetic waves and consumes \(100\) W of power. The amplitude of the electric field associated with the electromagnetic radiation at a distance of \(5\) m from the lamp will be:
1. \(1.34\) V/m
2. \(2.68\) V/m
3. \(4.02\) V/m
4. \(5.36\) V/m