Multiple Choice QuestionsIf E and B represent electric and magnetic field vectors of an electromagentic wave, the direction of propagation of the wave is along
E × B
B × E
E
B
Out of the following statements which is not true ?
Infrared radiations arise due to minor electron transitions in atoms
Infrared radiations are used for long distance photography
Sun is the natural source of infrared radiation
Infrared radiations are detected by using a bolometer
The condition under which a microwave oven heats up a food item containing water molecules most efficiently is
the frequency of the microwave must match the resonant frequency of the water molecules
the frequency of the microwave has no relation with natural frequency of water molecules
microwave are heat waves, so always produce heating
microwave are heat waves, so always produce heating
The decreasing order of wavelength of infrared, microwave, ultraviolet and gamma rays is
gamma rays, ultraviolet, infrared, microwaves
microwaves, gamma rays, infrared, ultraviolet
infrared, microwave, ultraviolet, gamma rays.
infrared, microwave, ultraviolet, gamma rays.
The energy of the EM waves is of the order of 15 keV. To which part of the spectrum does it belong?
X - rays
infrared rays
Ultraviolet rays
Ultraviolet rays
The velocity of electromagnetic radiation in a medium of permittivity 
and permeability 
is given by
The electric and magnetic field of an electromagnetic wave are:
in phase and parallel to each other
in opposite phase and perpendicular to each other
in opposite phase and parallel to each other
in opposite phase and parallel to each other
X-rays are
electromagnetic radiation
stream of electron
stream of proton
stream of uncharged particle
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