Electromagnetic waves practice · Medium

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

The electric field of an electromagnetic wave is given by $E=100 \sin \omega\left(t-\frac{x}{v}\right) N / C.$

Find the energy contained in a hypothetical space of volume $100 \mathrm{~cm}^3$

(Given $\left.\epsilon_0=9 \times 10^{-12} C^2 N^{-1} m^{-2}\right)$

The range of wavelengths for visible light is

Which of the following Maxwell's equation is valid for time varying conditions but not valid for static conditions:

Assertion: Radar is used to detect an aeroplane in the sky

Reason: Radar works on the principle of reflection of waves.

Assertion: In electromagnetic waves electric field and magnetic field lines are perpendicular to each other.

Reason: E and B are self - sustaining

Which of the following is correct?

Statement I: If earth did not have atmosphere, its average surface temperature would be lower than the present average surface temperature

Statement II: Greehouse effect would be absent if earth did not have atmosphere

A plane electromagnetic wave of wave intensity $6 {Wm}^{-2}$ strikes a small mirror of area $30 {~cm}^2$, held perpendicular to the approaching wave. The the mirror each second will be

If $\mathrm{E}$ and $\mathrm{B}$ denote electric and magnetic fields respectively, which of the following is dimensionless?

The intensity of electromagnetic wave is equal to (symbols have their usual meanings)

If the total electromagnetic energy falling on a surface is $U$, then the total momentum delivered (for complete absorption) is

The amplitude of the sinusoidally oscillating electric field of plane wave is $60\,\,\frac{V}{m}$. Then the amplitude of the magnetic field is

An accelerated charge will not produce

Statement I: Displacement current decreases with the increase in frequency of a.c. supplied to the capacitor

Statement II: Reactance due to capacitance is directly proprtional to the frequency of a.c.

The energy density associated with electric field $\vec{E}$ and magnetic field $\vec{B}$ of an electromagnetic wave in free space is given by $\left(\varepsilon_{0}-\right.$ permittivity of free space, $\mu_{0}$ - permeability of free space)

Maxwell in his famous equation of electromagnetism introduced the concept of

Biological importance of Ozone layer is

If value of electric field $E=6.3 \times 10^{27} \mathrm{volt} / \mathrm{m}$ for a electromagnetic wave. The value of magnetic field B will be:

Which of the following can be deflected in magnetic field?

A plane electromagnetic wave ${E_z} = 100\cos \left( {6 \times {{10}^8}t + 4x} \right)V/m$, where x is in metre and t is in second. Propagates in medium , what is refractive index of the medium ?

Cascade theory of showers of Cosmic rays is invented by

For a plane electromagnetic wave, average of which among the following is zero?

The magnetic field $B$ and electric field $E$ in an electromagnetic wave are:

In free space, an electromagnetic wave of 3 GHz frequency strikes over the edge of an object of size $\frac{\lambda }{{100}},$ where $\lambda$ is the wavelength of the wave in free space. The phenomenon, which happens there will be:

An electromagnetic wave of intensity $50\,\,W{m^{ - 2}}$ enters in a medium of refractive index ‘n’ without any loss. The ratio of the magnitudes of electric fields and the ratio of the magnitudes of magnetic fields of the wave before and after entering into the medium are respectively, given by

An earth orbiting satellite has solar energy collecting panel with total area $5\mathrm{\;}{\mathrm{m}^2}$. If solar radiations are perpendicular and completely absorbed, the average force associated with the radiation pressure is
(Solar constant$= 1.4\mathrm{\;kW}{\mathrm{m}^{ - 2}}$)

For an electromagnetic wave travelling in free space, the relation between average energy densities due to electric $({U_e})$ and magnetic $({U_m})$ fields is:

Statement I: A changing electric-field produces a magnetic field.

Statement II: A changing magnetic field produces an electric field.

Suppose that the electric field part of an electromagnetic wave in vacuum is $\vec{E}=(3.1 \mathrm{~N} / \mathrm{C}) \cos \left[(1.8 \mathrm{~rad} / \mathrm{m}) y+\left(5.4 \times 10^8 \mathrm{~rad} / \mathrm{s}\right) {t}\right] \hat{i}$. What is the frequency ${v}$?