BLOGGER TEMPLATES AND TWITTER BACKGROUNDS

Kamis, 22 Juli 2010



Electromagnetic waves



Electromagnetic waves are waves that can propagate even though there is no medium. Propagate in a wave of electromagnetic energy with a few characters that can be measured, namely: wavelength / wavelength, frequency, amplitude of / amplitude, velocity. Amplitude is the height of the wave, while the wavelength is the distance between the two peaks. Frequency is the number of waves passing through a node in one time unit. Frequency depends on the speed of the wave merambatnya. Because the speed of electromagnetic energy is constant (speed of light), wavelength and frequency is inversely proportional. The longer a wave, the lower the frequency, and the shorter the higher the frequency of a wave.

Electromagnetic energy emitted, or released, by all the time in the universe on a level that berbedabeda. The higher level of energy in an energy source, the lower the wavelength of the energy produced, and the higher frequency. Differences in the characteristics of the wave energy is used to classify electromagnetic energy.

The characteristics of electromagnetic waves:
From the description above we can conclude several characteristics of electromagnetic waves is as follows:

1. Changes in the electric field and magnetic field occurs at the same time, so that the two fields have a maximum and minimum prices at the same time and at the same place.

2. The direction of electric field and magnetic field perpendicular to each other and both perpendicular to the direction of wave propagation.

3. From the characteristics obtained that no two electromagnetic waves are transverse waves.

4. Like the waves in general, electromagnetic wave reflection events experienced, refraction, interference, and diffraction. Also experienced a polarization of the incident because it includes a transverse wave.

5. Propagation of electromagnetic waves depends only on the properties of electric and magnetic medium taken.

Light visible to the eye not only allows a kind of electromagnetic radiation. Opinions James Clerk Maxwell showed that electromagnetic waves other, in contrast to the light seen by the eyes in his wavelength and frequency, there may be. These theoretical conclusions are admirably reinforced by Heinrich Hertz, who could produce and meet the two waves are visible to the eye was predicted by Maxwell. A few years later Guglielmo Marconi demonstrated that the invisible waves that can be used to make eye communication without wires so what's his name menjelmalah radio. Now, we use also for television, X-ray, the gamma rays, infrared rays, ultraviolet rays are examples of electromagnetic radiation. Everything can be learned through Maxwell's brainchild.





SOURCE electromagnetic wave

1. Electrical oscillations.
2.  sunlight produces infrared rays.
3.  mercury lamp produces ultra violet.
4. Electron bombardment in a vacuum tube on metal pieces  produce X-rays (used for x-rays).

Unstable atomic nuclei produce gamma rays.



SPECTRUM electromagnetic wave

The composition of all forms of electromagnetic waves based on the wavelength and frequency is called the electromagnetic spectrum. Electromagnetic spectrum images below were prepared based on the wavelength (measured in units _m) includes a very low energy range, with wavelengths of high and low frequencies, like radio waves to very high energy, with a low wavelength and high frequency radiation such as X -ray and Gamma Ray.



Examples of the electromagnetic spectrum



Radio waves

Radio waves are classified according to wavelength, or frequency. If the wavelength is high, then the frequency must be low or vice versa. Frequency radio waves ranging from 30 kHz to above and are grouped according to broad frequency bands. Radio waves generated by the charge-accelerated electric charge through the wires penghantar. Charge-charge was raised by an electronic circuit called an oscillator. These radio waves emitted from the antenna and received by the antenna as well. You can not hear the radio directly, but the radio receiver will change the first wave energy into sound energy.



Microwaves

Microwaves (mikrowaves) is a radio wave with the highest frequency that is above 3 GHz. If the microwaves are absorbed by an object, so you will have the effect of warming on the thing. If the food absorb microwave radiation, then the food becomes hot in a very short time interval. The process is utilized in a microwave oven to cook food quickly and economically.

Microwaves are also used on aircraft RADAR (Radio Detection and Ranging) RADAR means finding and determine the trace of an object using microwaves. Radar aircraft using microwave reflection properties. Because glombang electromagnetic propagation c = 3 X 108 m / s, then by observing the time interval between transmitting the reception.


Infrared Rays

Infrared rays covering area up to 1014 Hz 1011Hz frequency or wavelength regions 10-4 cm to 10-1 cm. if you check the spectrum produced by a lamp with a detector which is connected to the miliampermeter, then a little above the tip of the needle ampermeter red spectrum. Rays are not seen but can be detected in the red spectrum is called infrared radiation.
Infamerah rays produced by electrons in the molecules vibrate because it diipanaskan. So every hot body would emit infrared light. Amount of infrared light emitted depends on temperature and color of objects.



Visible light

Visible light as electromagnetic radiation of the most well known by us can be defined as part of the electromagnetic wave spectrum that can be detected by human eye. Wavelength depending on the color looks nervariasi wavelengths ranging from approximately 4 x 10-7 m to light violet (purple) to 7x 10-7 m for a red light. Usefulness of light one of them is someone that the use of lasers in optical fiber telecommunications and medicine.


Ultraviolet rays

Ultraviolet light has a frequency in the range of 1015 Hz to 1016 Hz or in a long region gelombagn 10-8 m 10-7 m these waves are generated by atoms and molecules in electric flame. The sun is the main source of ultraviolet light emitting surface of the earth, the ozone layer is in the top layer that serves atmosferlah absorb ultraviolet rays and ultraviolet rays that pass does not endanger the lives of living beings on earth.


X-ray

X-rays have a frequency between 10 Hz to 10 Hz. very short wavelength of 10 cm to 10 cm. but even if such X-ray has a strong penetrating power, can penetrate thick books, a few centimeters thick wood and the aluminum plates 1 cm thick.


Gamma Rays

Gamma rays have a frequency between 10 Hz to 10 Hz or a wavelength of between 10 cm up to 10 cm. Greatest penetrating power, which causes serious effects if it is absorbed by body tissues.



Example application of electromagnetic waves in ordinary life day:

1.
1. Radio

Radio energy is the lowest form of electromagnetic energy levels, with a wavelength range from thousands of kilometers to less than one meter. The use most is communication, to investigate outer space and radar systems. Radar is useful for studying weather patterns, storms, making the 3D map of the earth's surface, measure rainfall, movement of ice in the polar regions and environmental monitor. Radar wavelengths ranging from 0.8 - 100 cm.

1.
1. Microwave

Microwave radiation wavelength range from 0.3 - 300 cm. Its use is primarily in the areas of communication and information delivery through open space, cooking, and PJ system is active. PJ active on the system, the microwave pulses were fired to a target and its reflection was measured to study the characteristics of the target. As an application example is Tropical rainfall's Measuring Mission (TRMM) Microwave Imager (TMI), which measures the microwave radiation that is emitted from the electromagnetic spectrum electromagnetic energy to measure the evaporation of the earth's atmosphere, water content in clouds and rain intensity.

1.
1. Infrared

Health conditions can be diagnosed by investigating the infrared emission from bodies. Special infrared photo called thermogram is used to detect blood circulation problems, arthritis and cancer. Infrared radiation can also be used in burglar alarms. A thief without his knowledge will impede the light and hid the alarm. Communicate with the TV remote control via infrared radiation generated by the LED (Light Emiting Diode) contained in the unit, so that we can turn on the TV from a distance using remote control.



d. Ultraviolet



UV light is needed in the assimilation of plants and can kill germs skin diseases.



e. X-ray



X-rays are commonly used in the medical field to capture the position of the bones in the body, particularly to determine the broken bone. However, the use of X-rays have to be careful because the network of human cells can be damaged by the use of X rays that are too long

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