Write the following radiations in ascending order in respect of their frequencies ; X-rays, Microwaves, UV rays and radiowaves.
Radiowaves, microwaves, UV-rays and X-rays.
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20
what is bandwidth ?
... is the range of frequencies occupied by a modulated radio-frequency signal, usually given in hertz
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shark
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lifesaver
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baam
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15
How are infrared waves produced?Write their one important use.
produced by hot bodies,molecules, used to take photographs in darkness and to study secret writin, also used in physical therapy
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10
How are radio waves produced?
produced by the accelerated motion of charges in conducting wires
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15
What are the directions of electric and magnetic field vectors relative to each other and relative to the direction of propagation of electromagnetic waves?
The oscillations of E and B fields are perpendicular to each other as well as to the direction of propagation of the wave.
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15
What is amplitude modulation?
Amplitude modulation is a process by which the wave signal is transmitted by modulating the amplitude of the signal, frequency remains constant.
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10
The speed of an electromagnetic wave in a material medium is given by v=1\âΞÎĩ. Ξ the permeability of the medium and Îĩ its permittivity. How does its frequency change?
Frequency remains unchanged.
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15
Determine the wavelength of the carrier wave for this transmission
500 m
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5
10
15
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25
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5
Which part of electromagnetic spectrum is used in radar systems? (
Microwave region of electromagnetic spectrum is used in radar systems.
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15
What is the FM?
the modulation of a radio or other wave by variation of its frequency, especially to carry an audio signal, amplitude of carrier wave remain constant
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20
State the name components of the frequency spectrum, determine the frequency of audio signal.
Carrier wave frequency=50 kHz,sidebands, audio signal f=5kHz
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10
A plane electromagnetic wave travels in vacuum along z-direction. What can you say about the direction of electric and magnetic field vectors?
The direction of electric field vector is along X-axis. Magnetic field vector is along Y-axis.
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5
Which part of electromagnetic spectrum is absorbed from sunlight by ozone layer?
Ultraviolet rays are absorbed from sunlight by ozone layers.