Recent questions and answers in Electromagnetic Waves

Electromagnetic waves are transverse in nature is evident by

answered Jan 30, 2020 by mohthapa

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A plane Electro magnetic wave of frequency $30\; MHZ$ travels in free space component of wave at a point $E= 6V/m$ along y direction . The magnetic field component B at this point would be

answered Mar 24, 2014 by meena.p

1 answer

S1: Radio waves can be polarized. \[\] S2: Sound waves in air are longitudinal in nature.

answered Mar 7, 2014 by thanvigandhi_1

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A sinusoidal electromagnetic plane wave travels through the empty space in $x$ - direction. The electric wave is polarized in the $y$ - direction frequency of waves is $1.5\: GHz$. At a certain point $P$ in space, the oscillating $E_y$ attains a maximum magnitude $E_o = 6.3 \: m V/m$ \[\] The direction of magnetic field vector is along?

answered Mar 5, 2014 by thanvigandhi_1

1 answer

A sinusoidal electromagnetic plane wave travels through the empty space in $x$ - direction. The electric wave is polarized in the $y$ - direction frequency of waves is $1.5\: GHz$. At a certain point $P$ in space, the oscillating $E_y$ attains a maximum magnitude $E_o = 6.3 \: V/m$ \[\] The direction of magnetic field vector is along?

answered Mar 5, 2014 by thanvigandhi_1

1 answer

A sinusoidal electromagnetic plane wave travels through the empty space in $x$ - direction. The electric wave is polarized in the $y$ - direction frequency of waves is $1.5\: GHz$. At a certain point $P$ in space, the oscillating $E_y$ attains a maximum magnitude $E_o = 6.3 \: mV/m$ \[\] The maximum magnitude $B_o$ of the magnetic field at the point is

answered Mar 5, 2014 by thanvigandhi_1

1 answer

A sinusoidal electromagnetic plane wave travels through the empty space in $x$ - direction. The electric wave is polarized in the $y$ - direction frequency of waves is $1.5\: GHz$. At a certain point $P$ in space, the oscillating $E_y$ attains a maximum magnitude $E_o = 6.3 \: V/m$ \[\] What is the wavelength of the wave?

answered Mar 5, 2014 by thanvigandhi_1

1 answer

According to electromagnetic wave theory, the electric and magnetic field vector associated with the wave is given by \[\] $|E| = E_{max} \cos(kx – \omega t)$ \[\] $|B| = B_{max} \cos(kx – \omega t)$ \[\] The energy of electromagnetic wave is confined in the form of electric and magnetic fields. The energy per unit volume in an electric field is given by $U_E = \large\frac{1}{2} \in_oE^2$ and the energy per unit volume in a magnetic field is given by $ U_M =\large\frac{1}{2} B^2/ \mu_0$ . The energy density associated with the magnetic field is equal to the energy density associated with the electric field. The total energy is equally shared by the electromagnetic as well as magnetic field. The rate of flow of energy in an electromagnetic wave is defined as pointing vector $S = 1/\mu_o (E \times B)$. A plane electromagnetic wave varies sinusoidally at $90\: MHz $ as it travels along the $+ve\: x$ direction. The peak value of the electric field is $2\: millivolt/m$ and it is directed along $ \pm y$ direction \[\] The average energy density in the radiation is

answered Mar 5, 2014 by thanvigandhi_1

1 answer

According to electromagnetic wave theory, the electric and magnetic field vector associated with the wave is given by \[\] $|E| = E_{max} \cos(kx – \omega t)$ \[\] $|B| = B_{max} \cos(kx – \omega t)$ \[\] The energy of electromagnetic wave is confined in the form of electric and magnetic fields. The energy per unit volume in an electric field is given by $U_E = \large\frac{1}{2} \in_oE^2$ and the energy per unit volume in a magnetic field is given by $ U_M =\large\frac{1}{2} B^2/ \mu_0$ . The energy density associated with the magnetic field is equal to the energy density associated with the electric field. The total energy is equally shared by the electromagnetic as well as magnetic field. The rate of flow of energy in an electromagnetic wave is defined as pointing vector $S = 1/\mu_o (E \times B)$. A plane electromagnetic wave varies sinusoidally at $90\: MHz $ as it travels along the $+ve\: x$ direction. The peak value of the electric field is $2\: millivolt/m$ and it is directed along $ \pm y$ direction \[\] The magnetic field vector as a function of time$(t)$ and space$(x)$ is

answered Mar 5, 2014 by thanvigandhi_1

1 answer

According to electromagnetic wave theory, the electric and magnetic field vector associated with the wave is given by \[\] $|E| = E_{max} \cos(kx – \omega t)$ \[\] $|B| = B_{max} \cos(kx – \omega t)$ \[\] The energy of electromagnetic wave is confined in the form of electric and magnetic fields. The energy per unit volume in an electric field is given by $U_E = \large\frac{1}{2} \in_oE^2$ and the energy per unit volume in a magnetic field is given by $ U_M =\large\frac{1}{2} B^2/ \mu_0$ . The energy density associated with the magnetic field is equal to the energy density associated with the electric field. The total energy is equally shared by the electromagnetic as well as magnetic field. The rate of flow of energy in an electromagnetic wave is defined as pointing vector $S = 1/\mu_o (E \times B)$. A plane electromagnetic wave varies sinusoidally at $90\: MHz $ as it travels along the $+ve\: x$ direction. The peak value of the electric field is $2\: millivolt/m$ and it is directed along $ \pm y$ direction \[\] The wavelength and period of the wave is respectively

answered Mar 5, 2014 by thanvigandhi_1

1 answer

Calculate the magnetic field between the plates at a point $15\: cm$ from the axis.

answered Mar 5, 2014 by thanvigandhi_1

1 answer

A $30\: pF$ capacitor has circular plates of area $100\: cm^2$. It is charged by a $70\: V$ battery through a $2\Omega$ resistor. At the instant, the battery is disconnected; the electric field between the plates is changing most rapidly. At this instant, find the rate of change of electric field between the plates.

answered Mar 5, 2014 by thanvigandhi_1

1 answer

A parallel plate capacitor as shown in the figure is made of circular plates each of radius $R = 6\: cm$, and it has a capacitance $C = 100\: pF$. The capacitor is connected to a $230\: V$ ac supply with a frequency of 300 rad/s. The amplitude $B$ at a point $3\: cm$ from the axis between the plates is

answered Mar 4, 2014 by thanvigandhi_1

1 answer

Calculate the electric field produced by the radiation coming from a $100\: W$ bulb at a distance of $3\: m$. Assume that the efficiency of the bulb is $2.5\ %$ and it is a point source.

answered Mar 4, 2014 by thanvigandhi_1

1 answer

A parallel plate capacitor with circular plates of radius $1\: m$ has a capacitance of $1\: nF$. At $t = 0$, it is connected for charging in series with a resistor $R= 1\: M\omega$ across a $2V$ battery. Calculate the magnetic field at a point $ P$, halfway between the centre and the periphery of the plates, after $t = 10–3s$. (The charge on the capacitor at time $t$ is $q (t) = CV [1 – exp (–t/\tau)]$, where the time constant $\tau$ is equal to $CR$.)

answered Mar 4, 2014 by thanvigandhi_1

1 answer

Electromagnetic waves travel in a medium at a speed of $2 \times 10^8 m/s$. The relative permeability of the medium is $1$. Calculate the relative permittivity.

answered Mar 4, 2014 by thanvigandhi_1

1 answer

A parallel plate capacitor with rectangular plates is being discharged. Consider a rectangular loop centered on the plates and between them. The loop measures a by $2a$, the plate measures $2a$ by $4a$. What fraction of the displacement current (i) is encircled by the loop?

answered Mar 4, 2014 by thanvigandhi_1

1 answer

A parallel plate capacitor with plate area $A$ and separation $d$ between the plates is charged by a constant current $i$. Consider a plane surface of area $ \large\frac{A}{2}$ parallel to the plates and drawn symmetrically between the plates. Find the displacement current through this area.

answered Mar 4, 2014 by thanvigandhi_1

1 answer

Which of the following statements is correct in relation to electromagnetic waves in an isotropic medium? (a) Energy due to electric field is equal to that due to magnetic field. (b) Electric vector E and, magnetic vector B are in phase. (c) For a given amplitude of E vector, the intensity increases as the first power of frequency f (d) For cylindrical wave fronts, the amplitude of the wave varies in proportion to $ \large\frac{1}{r^2}$ , where $r$ is the radius of the wave front.

answered Mar 4, 2014 by thanvigandhi_1

1 answer

S1: In an electromagnetic wave, the average energy density of electric field is equal to the average energy density of the magnetic field \[\] S2: Electric and magnetic fields are related as $E = cB$

answered Mar 3, 2014 by thanvigandhi_1

1 answer

The $rms$ value of the electric field of the light coming from the sun is $720\: N/C$. The average total energy density of the electromagnetic wave is

answered Mar 3, 2014 by thanvigandhi_1

1 answer

Given below are some famous numbers associated with electromagnetic radiations in different contexts in physics. Which of the following belongs to radio waves?

answered Mar 3, 2014 by thanvigandhi_1

1 answer

Calculate the energy of electromagnetic waves of wavelength $3000\: A^{\circ}.$

answered Mar 1, 2014 by thanvigandhi_1

1 answer

A plane electromagnetic wave in the visible region is moving along the $z$ direction. The frequency of the wave is $0.5 \times 10^{15}Hz$ and the electric field at any point is varying sinusoidally with time with amplitude of $1\: V/m$. Calculate the average values of densities of the magnetic field.

answered Mar 1, 2014 by thanvigandhi_1

1 answer

Find the average energy stored in a 60 cm length of a laser beam operating at $4\: mW.$

answered Mar 1, 2014 by thanvigandhi_1

1 answer

Find the amplitude of the electric field in a parallel beam of light of intensity $2\: W/m^2$

answered Mar 1, 2014 by thanvigandhi_1

1 answer

The electric field in an electromagnetic wave is given by $E = 50N/C\: \sin \omega (t-x/c)$. Find the energy contained in a cylinder of cross-section $10cm^2$ and length 50 cm along the x-axis.

answered Mar 1, 2014 by thanvigandhi_1

1 answer

The average energy flux of sunlight is $1\: kW/m^2$. This energy is falling normally on the plate surface of area $10\: cm^2$ which completely absorbs the energy. How much force is exerted on the plate if it is exposed to sunlight for 20 minutes?

answered Mar 1, 2014 by thanvigandhi_1

1 answer

The magnetic field in a plane electromagnetic wave is given by $B = 100\mu T \sin [(2 \times10^{15}s^{-1}) (t-x/c)]$. Calculate the average energy density corresponding to the electric field.

answered Mar 1, 2014 by thanvigandhi_1

1 answer

A light beam travelling in the x-direction is described by the electric field $E_y = 300 \: V/m \: \sin \omega\: (t – x/c)$. An electron is constrained to move along the y-direction with a speed of $2 \times 10^7 m/s$. Find the maximum magnetic force on the electron

answered Mar 1, 2014 by thanvigandhi_1

1 answer

A plane sinusoidal linearly polarized electromagnetic wave of wavelength $ 5 \times 10^{-7}m$ travels in vacuum in the direction of $x$ - axis. The average intensity of the wave per unit area is $0.1\: W/m^2$ and the plane of vibration of electric field is parallel to $y$ - axis. The equations describing the electric and magnetic field of this wave is

answered Mar 1, 2014 by thanvigandhi_1

1 answer