What is the energy density of electric field at a distance of 5 m from a point source of EM wave, if the electric field strength at that point be 100 V/m ?

(1) 44 x 10^-9 J/m³

(2) 11 x 10^-9 J/m³

(3) 22 x 10^-9 J/m³

(4) 88 x 10^-9 J/m³

Which one of the following rays (or waves) has maximum speed in air?

1. $\beta$-rays

2. Heat radiations

3. Cosmic rays

4. Ultrasonic waves

Which of the following phenomenon proves the transverse nature of electromagnetic waves?

1. Polarisation

2. Interference

3. Diffraction

4. Reflection

The impulse imparted by an electromagnetic pulse of energy 1.5 x 10^-2 joule when it falls normally on a perfectly reflecting surface is

1. 4 x 10^-10 kg-m/s

2. 2 x 10^-10 kg-m/s

3.10^-10 kg-m/s

4. 0.5 x 10^-10 kg-m/s

The electric field vector of an electromagnetic wave is given by, \(\vec{E}=E_0 \sin (\omega t-k x) \hat{j}.\) The corresponding expression for magnetic field is:$\stackrel{}{}$
1. \( \vec{B}=B_0 \sin (\omega t+k x) \hat{k} \)
2. \( \vec{B}=B_0 \sin (\omega t-k x) \hat{k} \)
3. \( \vec{B}=-B_0 \sin (\omega t+k x) \hat{k} \)
4. \( \vec{B}=-B_0 \sin (\omega t-k x) \hat{k}\)

Electromagnetic waves are produced by:

Figure shows a parallel plate capacitor being charged by a battery. If X and Y are two closed curves then during charging $\oint \overrightarrow{B}.d\overrightarrow{l}$ is zero along the curve

1. X only

2. Y only

3. Both X & Y

4. Neither X nor Y

For a transparent medium relative permeability and permittivity, \(\mu_r\) and \(\varepsilon_r\) are \(1.0\) and \(1.44\) respectively. The velocity of light in this medium would be:

The ratio of contributions made by the electric field and magnetic field components to the intensity of an electromagnetic wave is: (\(c\) = speed of electromagnetic waves)

Light with an average flux of \(20~\text{W/cm}^2\) falls on a non-reflecting surface at normal incidence having a surface area \(20~\text{cm}^2\). The energy received by the surface during time span of \(1\) minute is:
1. \(12\times 10^{3}~\text{J}\)
2. \(24\times 10^{3}~\text{J}\)
3. \(48\times 10^{3}~\text{J}\)
4. \(10\times 10^{3}~\text{J}\)