Recent questions tagged ch8

Electromagnetic wave with wave length $ \lambda$ is used in satellite communication . Identify and name the part of electromagnetic spectrum to which these radiation belong

asked Aug 20, 2016 by meena.p

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A variable frequency a.c source is connected to a capacitor .How will the displacement current change with decrease in frequency ?

asked Aug 20, 2016 by meena.p

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The charge on a parallel plate capacitor varies as $q= q_0 \cos 2 \pi \gamma t$ The plates are very large and close together (area aa , separation =d) Neglecting the edge effects, find the displacement current through the capacitor ?

asked Aug 20, 2016 by meena.p

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Why does microwave over heats up a food item containing water molecules more efficiently ?

asked Aug 20, 2016 by meena.p

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Why is the orientation of the protable radio with respect to broad casting station important ?

asked Aug 20, 2016 by meena.p

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The source of electromagnetic waves can be a charge

asked Aug 20, 2016 by meena.p

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A changed particle oscillates about its means equilibrium position with a frequency of $10^9$ Hz. The electromagnetic wave produced

asked Aug 20, 2016 by meena.p

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A plane electro magnetic wave propagating along x - direction can have following pair of $\overrightarrow{E}$ and $\overrightarrow{B}$

asked Aug 20, 2016 by meena.p

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An electro magnetic wave travels in vacuum along z direction $\overrightarrow{E}=(E_1 \hat i +E_2 \hat j) \cos (kz- wt)$ Choose the correct option from the following

asked Aug 19, 2016 by meena.p

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An EM wave radiation outwards from a dipole antenna with $E_0$ as the amplitude of its electric field vector . The electric field $E_0$ which transports significant energy from the source falls off as

asked Aug 19, 2016 by meena.p

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If $\overrightarrow{E}$ and $\overrightarrow{B}$ represent electric and magnetic field vectors of the electro magnetic wave is along

asked Aug 19, 2016 by meena.p

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The electric field intensity produced by the radiation coming from $100\;w$ bulls at a $3\;m$ distance is E. The electric field intensity produced by the radiation coming from 50 w bulb at the same distance is :

asked Aug 19, 2016 by meena.p

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Light with an energy flux of $20w/cm^2$ falls on a non- reflectiy surface has an area of $30\;cm^2$ , the total momentum delivered (for complete absorption ) during 30 minutes is

asked Aug 19, 2016 by meena.p

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The ratio of contribution made by the electric and magnetic field components to the intensity of an EM wave is

asked Aug 19, 2016 by meena.p

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A linearly polarized electromagnetic wave given as $E=E_0 \hat i \cos (kz-wt)$ is incident normally on a perfectly reflecting infinite wall at $z=a$ Assuming that the material of the wall is optically inactive , the reflected wave will be given as

asked Aug 19, 2016 by meena.p

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One requires $11\;ev$ of energy to dissociate a carbon monoxide molecule into carbon and oxygen atoms. The minimum frequency of the appropriate electromagnetic radiation to achieve dissociation lies in

asked Aug 18, 2016 by meena.p

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Some scientists have predicted that a global nuclear war on the earth would be followed by a severe nuclear winter with a devastating effect on life on earth. What might be the basis of their prediction ?

asked Aug 18, 2016 by meena.p

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If the earth did not have atmosphere would its average temperature be higher or lower than it is now ?

asked Aug 18, 2016 by meena.p

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The small ozone layer on the top of the atmosphere is for human survival on why ?

asked Aug 18, 2016 by meena.p

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Optical and radio telescopes are built on the ground but x- ray astronomy is possible only from satellite orbiting the earth . why ?

asked Aug 18, 2016 by meena.p

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It is necessary to use satellites for long distance T.V transmission . Why ?

asked Aug 18, 2016 by meena.p

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Long distance ratio broad casts use short wave bands why ?

asked Aug 18, 2016 by meena.p

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State the parts of e.m spectrum to which $14.4\;kev$ (energy of a particular transition $Cn Fe^{57} $ nucleus associated with a famous high resolution spectroscopic method Massbauer spectroscopy ]

asked Aug 18, 2016 by meena.p

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State the parts of e.m spectrum to which $5890^{\circ} A - 5896 ^{\circ} A$ (double lines of sodium).

asked Aug 18, 2016 by meena.p

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State the parts of e.m spectrum to which $2.7 \;k$ (temperature with isotropic radiation filly all space - through to be a relic of the big bang origin of the universe ).

asked Aug 18, 2016 by meena.p

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State the part of the spectrum to which $1057\;MHz$ [frequency of radiation arising from two close energy levels in hydrogen known as lamb shift .

asked Aug 18, 2016 by meena.p

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State the part of the spectrum to which $21\;cm$ (wave length emitted by atomic hydrogen in interstellar space)

asked Aug 18, 2016 by meena.p

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About $5\%$ of the power of a low light bulb is converted to visible radiation . What is the average intensity of visible radiation , at a distance of $10\;m$. Assume that the radiation is emitted isotropic-ally and neglect reflection .

asked Aug 18, 2016 by meena.p

1 answer

About $5\%$ of the power of a low light bulb is converted to visible radiation . What is the average intensity of visible radiation , at a distance of 1m from the bulb ?

asked Aug 18, 2016 by meena.p

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Suppose that the electric field part of an electromagnetic wave in vaccum is $E= 3.1 \times N/c $ an $[(1/8 rad/m)y +(5.4 \times 10^8\;rad/s/t)$ what is the amplitude of the magnetic field part of the wave ?

asked Aug 18, 2016 by meena.p

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Suppose that the electric field part of an electromagnetic wave in vaccum is $E= 3.1 \times N/c $ an $[(1/8 rad/m)y +(5.4 \times 10^8\;rad/s/t)$ write an expression for the magnetic field part of the wave

asked Aug 18, 2016 by meena.p

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Suppose that the electric field part of an electromagnetic wave in vaccum is $E= 3.1 \times N/c $ an $[(1/8 rad/m)y +(5.4 \times 10^8\;rad/s/t)$ what is the frequency of $\gamma$

asked Aug 17, 2016 by meena.p

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Suppose that the electric field part of an electromagnetic wave in vaccum is $E= 3.1 \times N/c $ cos $[(1/8 rad/m)y +(5.4 \times 10^8\;rad/s/t)$ what is the amplitude of the magnetic field part of the wave ?

asked Aug 17, 2016 by meena.p

1 answer

Suppose that the electric field part of an electromagnetic wave in vaccum is $E= 3.1 \times N/c $ an $[(1/8 rad/m)y +(5.4 \times 10^8\;rad/s/t)$ what is the direction of motion ?

asked Aug 17, 2016 by meena.p

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In a plane electromagnetic wave, the electric field oscillates sinusoidal at a frequency of $2.0 \times 10^{10}\;Hz$ and amplitude $48 vm^{-1}$. What is the wavelength of the wave ?Show that the total average energy density of magnetic field $( c= 3 \times 10^8 ms^{-1})$

asked Aug 17, 2016 by meena.p

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In a plane electromagnetic wave, the electric field oscillates sinusoidal at a frequency of $2.0 \times 10^{10}\;Hz$ and amplitude $48 vm^{-1}$. What is the wavelength of the wave ?

asked Aug 17, 2016 by meena.p

1 answer

Suppose that the electric field amplitude of an electromagnetic wave is $E_0 = 120 N/C$ and its frequency is $\gamma = 50.0 \;MHz$ . Find the expression of $\overrightarrow{E}$ and $\overrightarrow{B}$

asked Aug 17, 2016 by meena.p

1 answer

Suppose that the electric field amplitude of an electromagnetic wave is $E_0 = 120 N/C$ and its frequency is $\gamma = 50.0 \;MHz$ . Determine $B_0, w,k$ and $\lambda$

asked Aug 17, 2016 by meena.p

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The amplitude of the magnetic field part of a harmonic electro magnetic wave in vaccum is $B_0 =510\;nT$. What is the amplitude of the electric field part of the wave ?

asked Aug 17, 2016 by meena.p

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A changed particle oscillates about its mean equilibrium position with a frequency of $10^9\;Hz$. What is the frequency of electromagnetic waves produced by the oscillator ?

asked Aug 17, 2016 by meena.p

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A radio can tune any station in the $7.5 \;MHz$ to $12\;MHz$ band . What is the corresponding wave length band ?

asked Aug 17, 2016 by meena.p

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A plane electro magnetic wave travels in vaccum along z- direction . What can you say about the direction of its electric and magnetic field vectors ? If the frequency of the wave is $30\;MHz$ What is its wave length ?

asked Aug 17, 2016 by meena.p

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What physical quantity is the same for x- rays of wave length $10^{-10}m$ red light of wave length $6800A^{\circ}$ and radio waves of wave length $500\;m$?

asked Aug 17, 2016 by meena.p

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A parallel plate capacitor made of circular plates each of radius $R=6.0\;cm$ has a capacitance $c= 100\;pF$. The capacitor is connected to a $230\;v$ a.c supply with an angular frequency of $300\;rad\;S^{-1}$ . What is the r.m.s value of the conduction current ?.Is the conduction current equal to the displacement current ?

asked Aug 16, 2016 by meena.p

1 answer

A parallel plate capacitor made of circular plates each of radius $R=6.0\;cm$ has a capacitance $c= 100\;pF$. The capacitor is connected to a $230\;v$ a.c supply with an angular frequency of $300\;rad\;S^{-1}$ . What is the r.m.s value of the conduction current ?Determine the magnitude of Bata point 3.0 cm from the axis between the plates

asked Aug 16, 2016 by meena.p

1 answer

A parallel plate capacitor made of circular plates each of radius $R=6.0\;cm$ has a capacitance $c= 100\;pF$. The capacitor is connected to a $230\;v$ a.c supply with an angular frequency of $300\;rad\;S^{-1}$ . What is the r.m.s value of the conduction current ?

asked Aug 16, 2016 by meena.p

1 answer

The figure shows a capacitor made of two circular plate each of radius 12 cm and separated and separated by 5.0 mm . The capacitor is being changed by an external source (not shown in the figure ). The changing current is constant and equal to $0.15\;A$ Calculate the capacitor and the rate of change of potential difference between the plates. Is Kischoff's first rule valid at each plate of the capacitor?

asked Aug 16, 2016 by meena.p

1 answer

The figure shows a capacitor made of two circular plate each of radius 12 cm and separated and separated by 5.0 mm . The capacitor is being changed by an external source (not shown in the figure ). The changing current is constant and equal to $0.15\;A$ Calculate the capacitor and the rate of change of potential difference between the plates.obtain the displacement

asked Aug 16, 2016 by meena.p

1 answer

The figure shows a capacitor made of two circular plate each of radius 12 cm and separated and separated by 5.0 mm . The capacitor is being changed by an external source (not shown in the figure ). The changing current is constant and equal to $0.15\;A$ Calculate the capacitor and the rate of change of potential difference between the plates

asked Aug 16, 2016 by meena.p

1 answer

The following pictograph shows the number of absentees in a class of 30 students during the previous week. On which day were the maximum number of students absent?

asked Aug 2, 2016 by meena.p

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