Recent questions tagged ch8

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 $E = cB$

asked Mar 3, 2014 by thanvigandhi_1

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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

asked Mar 3, 2014 by thanvigandhi_1

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

asked Mar 3, 2014 by thanvigandhi_1

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

asked Mar 1, 2014 by thanvigandhi_1

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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.

asked Mar 1, 2014 by thanvigandhi_1

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

asked Mar 1, 2014 by thanvigandhi_1

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

asked Mar 1, 2014 by thanvigandhi_1

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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.

asked 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?

asked Mar 1, 2014 by thanvigandhi_1

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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.

asked 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

asked 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

asked Mar 1, 2014 by thanvigandhi_1

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A $60W$ monochromatic point source radiating equally in all directions in vacuum is being monitored at a distance of $2m$. Determine the amplitude if the electric field.

asked Mar 1, 2014 by thanvigandhi_1

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A laser emits a beam of light of $2mm$ diameter. If the power of beam is $10mW$, the intensity of the beam of light is

asked Feb 28, 2014 by thanvigandhi_1

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We can establish an instantaneous displacement current of $1\: A$ in the space between the two plates of a $1\: \mu\: F$ parallel plate capacitor by varying voltage at the rate of

asked Feb 28, 2014 by thanvigandhi_1

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A parallel plate capacitor has circular plates, each of radius $5\: cm$. It is being charged so that electric field in the gap between its plates rises steadily at the rate of $10^{12}V/ms$. What is the displacement current?

asked Feb 28, 2014 by thanvigandhi_1

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A radio wave of intensity $I$ is reflected by a surface. The intensity $ (I)$, if pressure exerted on the surface is $2 \times 10^{-8} N/m^2$ , will be:

asked Feb 28, 2014 by thanvigandhi_1

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What is order of energy of X-rays $(E_X)$, radio waves $(E_R)$, and micro waves $(E_M)$?

asked Feb 28, 2014 by thanvigandhi_1

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Some radio waves of frequency of about $1.5 \times 10^9$ Hz were received by a radio-telescope from distant star. If the speed of the waves is $3 \times 10^5 \: km/s$, then the wave- length of the wave will be:

asked Feb 28, 2014 by thanvigandhi_1

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An object is placed at some distance from a radio station. If the interval between transmission and reception of pulses is $2.66 \times 10^{-2}\: sec$, then the distance is:

asked Feb 28, 2014 by thanvigandhi_1

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The speed of light in air, if an electromagnetic wave is travelling in air whose dielectric constant is $k = 1.006$, will be :

asked Feb 28, 2014 by thanvigandhi_1

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The energy of photon of electromagnetic radiation of wavelength = $2000\: A^{\circ}$ is:

asked Feb 28, 2014 by thanvigandhi_1

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If an electromagnetic wave of frequency $v = 3.0\: MHz$ passes from vacuum into a dielectric medium with permittivity $e = 4.0$ then

asked Feb 28, 2014 by thanvigandhi_1

1 answer