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A laser beam can be focussed on an area equal to the square of its wavelength. A He-Ne laser radiates energy at the rate of 1mW and its wavelength is 600 nm The intensity of focussed beam will be
The correct answer is:
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An electromagnetic radiation has an energy 14.4 KeV. To which region of electromagnetic spectrum does it belong?
An electromagnetic radiation has an energy 14.4 KeV. To which region of electromagnetic spectrum does it belong?
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A point source of electromagnetic radiation has an average power output of 800W. The maximum value of electric field at a distance 3.5 m from the source will be 62.6 V/m, the energy density at a distance 3.5 m from the source will be - (in joule/m3)
A point source of electromagnetic radiation has an average power output of 800W. The maximum value of electric field at a distance 3.5 m from the source will be 62.6 V/m, the energy density at a distance 3.5 m from the source will be - (in joule/m3)
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In the above question the radiation force on the mirror will be
In the above question the radiation force on the mirror will be
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A plane electromagnetic wave of wave intensity 6W/m2 stikes a small mirror of area 40cm2 , held perpendicular to the approaching wave. The momentum transferred by the wave to the mirror each second will be
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The magnetic field in travelling EM wave has a peak value of 20nT. The peak value of electric field strength is.
The magnetic field in travelling EM wave has a peak value of 20nT. The peak value of electric field strength is.
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A wave is propagating in a medium of dielectric constant 2 and relative permeability 50. The wave impedance is
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The wave emitted by any atom or molecule must have some finite total length which is known as the coherence length. For sodium light, this length is 2.4cm. The number of oscillations in this length will be Given l = 5900
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An AC rms voltage of 2V having a frequency of 50 KHz is applied to a condenser of capacity of 10mF The maximum value of the magnetic field between the plates of the condenser if the radius of plate is 10cm is
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A condenser has two conducting plates of radius 10cm separated by a distance of 5mm. It is charged with a constant current of 0.15A. The magnetic field at a point 2cm from the axis in the gap is
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A parallel plate condenser has conducting plates of radius 12cm separated by a distance of 5mm. It is charged with a constant charging current of 0.16 A, the rate at which the potential difference between the plate change is
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A parallel plate condenser consists of two circular plates each of radius 2cm separated by a distance of 0.1mm. A time varying potential difference of 
is applied across the plates of the condenser. The displacement current is
A parallel plate condenser consists of two circular plates each of radius 2cm separated by a distance of 0.1mm. A time varying potential difference of is applied across the plates of the condenser. The displacement current is
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The intensity of TV broad cast station of ( 
V/M is...... and the wave length in meter is ......
The intensity of TV broad cast station of ( V/M is...... and the wave length in meter is ......
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The sun radiates electromagnetic energy at the rate of 
Its radius is 
The intensity of sun light at the solar surface will be (in W/m2)
The sun radiates electromagnetic energy at the rate of Its radius is The intensity of sun light at the solar surface will be (in W/m2)
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Maths-
is equal to
is equal to
Maths-General
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About 5% of the power of a 100 W light bulb is converted to visible radiation. The average intensity of visible radiation at a distance of 1 m from the bulb:
About 5% of the power of a 100 W light bulb is converted to visible radiation. The average intensity of visible radiation at a distance of 1 m from the bulb:
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