What is the difference and role of electromagnetic waves in long wave, medium wave, short wave, and

in electromagnetic waves'Long wave'Medium wave'Shortwave'Microwave'What is the difference and role.

It mainly relies on the propagation of ground waves along the earth's surface, which has low propagation loss and strong diffraction ability. Ultra-long waves with a frequency of less than 30kHz can travel around the globe. When the long wave propagation, it has the advantages of stable propagation and little influence by nuclear and atmospheric disturbances.

It spreads in seawater and soil, and the absorption loss is also small. Due to the need for a huge antenna equipment for long waves, China's radio stations do not use long wave (LW) bands, which are mainly used for communication with submarines and ships for ocean voyages. Therefore, domestic radios generally do not have long-wave (LW) bands.

The shorter the wavelength, the stronger the penetration, so X-rays are often used for human fluoroscopy.

The shorter the wavelength, the higher the energy and the stronger the penetrating power.

This is not a ,...... of penetrating abilityRadio waves (long-wave, medium-wave, short-wave, microwave) all have relatively long wavelengths, from m to km, with small frequencies and low energy.

They are very wave-like, particle-less and rely mainly on diffraction to cross obstacles, and from this point of view, the wavelength of long waves is long, and the scale of obstacles crossed is also large.

The shorter the wavelength, the closer it is to the linear propagation nature of light.

The microwave band (decimeter and centimeter wave) is already moving straight like light through the ionosphere and propagating at line-of-sight, so the base station is set up for wireless communication.

Snow, rain, and fog can cause microwave attenuation.

And the millimeter wave band is called "quasi-optical".

The ability of short waves to penetrate the atmospheric ionosphere is not strong.

It is reflected many times between the higher atmospheric ionosphere and the surface, and the long waves propagated along the surface, also called ground waves, were reflected to the surface by the very low ionosphere, and propagated by diffraction, and tended to the surface.

The medium wave is between the long wave and the short wave.

The shorter the wavelength, the closer it is to the linear propagation nature of light, and the microwave band (decimeter and centimeter wave) has begun to penetrate the ionosphere and propagate according to the line-of-sight like light, so wireless communication needs to establish a base station, snow, rain, fog will cause microwave attenuation, and to the millimeter band, it is called "quasi-optics", and the ability of short waves to penetrate the atmospheric ionosphere is not strong, it is reflected many times between the higher atmospheric ionosphere and the earth's surface, and the refraction propagation, and the long wave propagates along the surface, also called ground waves, and is reflected to the surface by the very low ionosphere, and propagates by diffraction and tends to the surface Medium wave Ma between long wave and short wave View the original post" to adopt it.

The difference between these waves is the length of the wavelength.

Long wave 30000 3000 meters.

Medium wave 3000 200 m for telegraph, radio short wave 50 10 m same as medium wave.

Microwave 10 m 1 mm TV, radar.

If the radar wants to detect a long distance, then the interval between the two electromagnetic pulses it emits should be slightly larger, and the pulse wavelength should be slightly longer, so that the radar wave will be longer and reflected back when it encounters the object, and the distance will be far. So choose shorter wavelength waves, so most radars emit microwaves.

...Radar is divided into meter-wave radar, decimeter-wave radar, centimeter-wave radar, millimeter-wave radar, laser infrared radar, and so on.

Short wave refers to radio waves with a frequency of 3 30MHz.

Medium wave refers to radio waves with a frequency of 300kHz 3MHz.

Long waves (including ultra-long waves) refer to radio waves with a frequency of less than 300kHz.

FM radio FM is a broadcasting technology in which the frequency of high-frequency oscillations varies with the amplitude of an audio signal.

Due to the high working frequency of FM broadcasting, it can be far away from various interference signals (such as factory interference, lightning, etc.), so it is not easy to be interfered with.

FM radio can transmit a wide audio frequency band, which is suitable for transmitting high-fidelity ** programs, so the sound quality of FM radio is much better than that of AM broadcasting.

The wavelength of ultra-long wave is 100,000 meters to 10,000 meters, and the frequency is 3 30 kHz; The wavelength of the long wave is 10,000 m 1,000 m and the frequency is 30 300 kHz; The wavelength of the medium wave is 1,000 meters to 100 meters, and the frequency is 300 kHz MHz; Short waves have a wavelength of 100 meters to 10 meters and a frequency of megahertz; Ultra-short waves have a wavelength of 10 m 1 mm and a frequency of 30 300,000 MHz (Note: ultra-short waves with a wavelength of less than 1 m are also called microwaves).