Electromagnetic waves practice · Medium

An electromagnetic wave travels along $z$-axis. Which of the following pairs of space and time varying fields would generate such a wave

The electromagnetic waves do not transport

The intensity contribution of electric field in the net intensity of EM wave is I. The value of half of intensity contribution due to magnetic field will be

The reative permeability of glass is 3/8 and the dielectric constant of glass is 8. The refractive index of glass is

Assertion: The average magnitude of Pointing vectors $\overrightarrow{\mathrm{S}}$ is the intensity of electromagnetic wave.

Reason: Poynting vector is given by $\overrightarrow{\mathrm{S}}=\frac{\overrightarrow{\mathrm{E}} \times \overrightarrow{\mathrm{B}}}{2 \mu_0}$.

The intensity of sunlight (in $\mathrm{W} / \mathrm{m}^2$) at the solar surface will be

Laser beams are used to measure long distance because

Identify the correct statements from the following descriptions of various properties of electromagnetic waves.
(A) In a plane electromagnetic wave electric field and magnetic field must be perpendicular to each other and direction of propagation of wave should be along electric field or magnetic field.
(B) The energy in electromagnetic wave is divided equally between electric and magnetic fields.
(C) Both electric field and magnetic field are parallel to each other and perpendicular to the direction of propagation of wave.
(D) The electric field, magnetic field and direction of propagation of wave must be perpendicular to each other.
(E) The ratio of amplitude of magnetic field to the amplitude of electric field is equal to speed of light.
Choose the most appropriate answer from the options given below

The wavelength of infrared rays is of the order of

In a uniform magnetic field of ${10^{ - 5}}T$ in free space, the energy density is u. The electric field which will produce the same energy density in free space is

To establish an instantaneous displacement current of 2 A in the space between two parallel plates of $1\,\mu F$ plates will have to be changed at the rate of

Maxwell’s set of equation encapsulated basic laws such as

The average value of electric energy density in an Electromagnetic Waves is (${E_0}$ is peak value)

Which of the following shows green house effect

The magnetic field between the plate of a capacitor where $r > R$ is given by (where $r$ is the distance from the axis of plates and $R$ is the radius of each plate of capacitor)

A point source of electromagnetic radiation has an average power output of $1500 \mathrm{~W}$. The maximum value of electric field at a distance of $3 \mathrm{~m}$ from this sources in $\mathrm{Vm}^{-1}$ is

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

The decreasing order of wavelength of infrared, microwave, ultraviolet and gamma rays is

Dimensions of $\varepsilon_0 \mathrm{~d} \phi / \mathrm{dt}$ is

The infra-red spectrum lies between

If a free electron is placed in the path of a plane electromagnetic wave, it will start moving along

Which of the following electromagnetic waves have minimum frequency

A plane EM wave is propagating along $x$ direction. It has a wavelength of $4 \mathrm{~mm}$. If electric field is in $y$ direction with the maximum magnitude of $60 \mathrm{~Vm}^{-1}$, the equation for magnetic field is:

Statement I: Microwaves have more energy than the radio waves

Statement II: Microwaves have greater wavelength than the radiowaves

Which of the following rays is emitted by a human body?

A point source is placed at origin. Its intensity at distance of $2 \mathrm{~cm}$ from source is $I$ then intensity at distance $4 \mathrm{~cm}$ from the source shall be.

Ozone layer blocks the radiations of wavelength

An EM wave from air enters a medium. The electric fields are ${E_1} = {E_{01}}\hat x\cos \left[ {2\pi v\left( {\frac{z}{c} - t} \right)} \right]$ in air and ${E_2} = {E_{02}}\hat x\cos \left[ {k\left( {2z - ct} \right)} \right]$ in medium, where the wave number k and frequency ν refer to their values in air. The medium is non-magnetic.
If ${\varepsilon _{{r_1}}}$ and ${\varepsilon _{{r_2}}}$ refer to relative permittivities of air and medium respectively, which of the following options is correct?

Radio waves and visible light in vacuum have

The magnetic field of a beam emerging from a filter facing a floodlight is given by

$\mathrm{B}_0=12 \times 10^{-8} \sin ( 1.20 \times 10^7 \mathrm{z} \left.-3.60 \times 10^{15} \mathrm{t}\right) \mathrm{T}$.

What is the average intensity of the beam?