The velocity of electromagnetic radiation in a medium of permittivity ${\epsilon }_0$ and permeability ${\mu }_0$ is given by:

1.  $\sqrt{\frac{{\mathrm{\epsilon }}_{\mathrm{o}}}{{\mathrm{\mu }}_{\mathrm{o}}}}$

2.  $\sqrt{{\mathrm{\mu }}_{\mathrm{o}}{\mathrm{\epsilon }}_{\mathrm{o}}}$

3.  $\frac{1}{\sqrt{{\mathrm{\mu }}_{\mathrm{o}}{\mathrm{\epsilon }}_{\mathrm{o}}}}$

4.  $\sqrt{\frac{{\mathrm{\mu }}_{\mathrm{o}}}{{\mathrm{\epsilon }}_{\mathrm{o}}}}$

The electric and magnetic fields of an electromagnetic wave are:

Which colour of the light has the longest wavelength?

A parallel plate capacitor of capacitance \(20~\mu\text{F}\) is being charged by a voltage source whose potential is changing at the rate of \(3~\text{V/s}.\) The conduction current through the connecting wires, and the displacement current through the plates of the capacitor would be, respectively:
1. zero, zero
2. zero, \(60~\mu\text{A}\)
3. \(60~\mu\text{A},\) \(60~\mu\text{A}\)
4. \(60~\mu\text{A},\) zero

Which of the following statement is false for the properties of electromagnetic waves?

The electric and the magnetic fields, associated with an electromagnetic wave, propagating along the positive Z-axis, can be represented by:
1. \(\left [E=E_{0}\hat{k},~B=B_{0}\hat{i} \right ]\)
2. \(\left [E=E_{0}\hat{j},~B=B_{0}\hat{j} \right ]\)
3. \(\left [E=E_{0}\hat{j},~B=B_{0}\hat{k} \right ]\)
4. \(\left [E=E_{0}\hat{i},~B=B_{0}\hat{j} \right ]\)

Light with an energy flux of \(25\times10^4\) Wm^–2 falls on a perfectly reflecting surface at normal incidence. If the surface area is \(15\) cm², the average force exerted on the surface is:
1. \(1.25\times 10^{-6}\) N
2. \(2.50\times 10^{-6}\) N$$
3. \(1.20\times 10^{-6}\) N$\mathrm{}$
4. \(3.0\times 10^{-6}\) N

Out of the following options which one can be used to produce a propagating electromagnetic wave?

A \(100~\Omega\)$\mathrm{}$ resistance and a capacitor of \(100~\Omega\)$\mathrm{}$ reactance are connected in series across a \(220~\text{V}\) source. When the capacitor is \(50\%\) charged, the peak value of the displacement current is:
1. \(2.2~\text{A}\)
2. \(11~\text{A}\)
3. \(4.4~\text{A}\)
4. \(11\sqrt{2}~\text{A}\)