Electromagnetic WavesElectromagnetic waves are waves that do not require the propagation medium . Waves
on a string , waves on the water surface , and the sound waves are
mechanical waves , ie waves that require a medium to propagate . Electromagnetic waves consist of a wide - range of different wave
frequency and wavelength , but the speed is the same diruang vacuum , ie c = 3 x 108 m/s.
The order of the spectrum of electromagnetic waves of frequencies ranging sorted smallest to largest frequency is :
1 . Waves Radio 5 . Rays Looks ( light )2 . Waves TV 6 . Ultraviolet3 . Microwave ( radar ) 7 . Rays X4 . Infrared Rays 8 . Rays Gamma
The relationship between the frequency ( f ) , wavelength ( λ ) , and the propagation of electromagnetic wave ( c ) is
Gelombang Radio
Radio waves can be generated by the electronic circuit called an oscillator. The radio waves emitted from the antenna and received by the antenna anyway. The total area covered and the wavelength to be generated can be determined from the low height antenna. These radio waves can not be heard directly, but the radio receiver will change the first wave energy into sound energy.
Grouping radio wave frequency and wavelength based on the table below:
wide frequency
|
Wavelength
|
some use of
|
Low
(LF)
30 kHz
– 300 kHz
|
Long Wave
1500 m
|
And long wave radio communications over long distances
|
Medium
(MF)
300
kHz – 30 MHz
|
Medium Wave
300 m
|
Local and medium wave radio remote
|
High
(HF)
3 MHz
– 30 MHz
|
Short Wave
30 m
|
Shortwave radios and amateur radios and CB communication
|
Very
High (VHF)
30 MHz
– 300 MHz
|
Veryshort Wave
3 m
|
FM radio, police, and emergency services
|
Ultrahigh
(UHF)
300
MHz – 3 GHz
|
Ultrashort Wave
30 cm
|
TV
|
Superhigh
(SHF)
Diatas
3 GHz
|
Microwaves
3 cm
|
Radar,satellite communications, telephone and TV channels
|
Television Waves
With a slightly higher frequency than the radio, the television waves propagate straight, can not be reflected by layers - lapiosan atmosferbumi. To catch the television broadcast station Jakarta, then Bandung a liaison stasin (relay) which is the peak of Mount Tangkuban Perahu. For more distant regions, such as eastern Indonesia, needed a satellite as a liaison station.
Micro wave (microwave) with a frequency of 3 GHz can be used for communication tools, cooking and radar. Radar antenna can act as a transmitter and receiver of electromagnetic waves. If the time interval between sending and receiving kesasaran pulses reflected from the target pulse is Δt, then the distance of the target's radar kepusat, is
S = C . Δt / 2
Infrared light can not be scattered by the particles - airborne particles so by using the plate - a piece of film sensitive to infrared wavelengths. Note that infrared light can not be detected by the naked eye.
Looks Ray
Visible light is called the light ray vision that can help us. In order objects - objects invisible, visible light is needed. Rays seemed to be on a fairly narrow frequency range with a wavelength between (430 m - 690 nm), with a spectrum of colors ranging from large wavelength is red, orange, yellow, green, blue, indigo, violet. So, purple has the smallest wavelength.
Ultraviolet or ultraviolet rays generated by atoms - atoms and molecules. Most of the atom emits light with a frequency - a frequency that is typical in the region of visible light and ultraviolet light. Ultraviolet light has a frequency between 1015 Hz – 1016 Hz. The sun is the main source of ultraviolet. Ozone (O3) diatmosfer serves to absorb the rays. Perforation of the ozone layer in the atmosphere can increase the ultraviolet light to the surface of the earth. It is living life threatening makhluh surface of the earth.
X-rays by Wilhelm Conrad Roentgen discovered X-rays so often called Roentgen rays. X-rays produced by electrons - the electrons are located in the inner electron shell of an atom. X-rays have very short wavelengths, X-rays have a very strong penetrating power. Frequency between. 1016 Hz – 1020 Hz. X-rays are widely used in medicine and in industry and can be used to detect organ - an organ in the body is also used to photograph the position of the bones in the body such as bone fractures.
Gamma Rays
Gamma rays have a frequency between 1020 Hz – 1025 Hz, and an electromagnetic wave that has the greatest frequency. Gamma rays produced by the nucleus - atomic nuclei are stable. Gamma rays have very great penetrating power, can penetrate the metal plate with a thickness of a few centimeters.
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