Electromagnetic Radiation

Night vision technology typically uses the infrared band of the electromagnetic spectrum. This allows cameras or goggles to detect heat signatures emitted by objects, even in low light conditions.

Electromagnetic waves

If it is 1000 watts then it produces a 1000 watts. A watt is 1 joule/sec.

Fluorescence agents are chemicals that emit light upon excitation. In the context of uranium glow in the dark items, such as glassware or jewelry, fluorescence agents are often integrated to enhance the glow by absorbing energy from UV light and reemitting it as visible light, resulting in a brighter and longer-lasting glow.

low penetrating power, for example, Uv light. Uv light has longer wavelenth than gamma ray and x-ray, therefor has lower penetrating power. It can only sterilize surfaces and heat sensitive items.

1. Light IS energy - and is mass-less, thus without substance.
2. Light is a form of energy, there is no substance that give it energy. It is the energy contained in oscillating electromagnetic fields. It isn't purely electric or magnetic. Electric fields have the property of inducing a corresponding perpendicular magnetic field when they change. And changing magnetic fields similarly produce a perpendicular electric field. These changes in the fields propagate outwards in the form of "electromagnetic waves". So it is more sensible to consider magnetism and electricity as two parts of the same coin.

   James Clerk Maxwell put all the laws of electricity and magnetism together and came up with Maxwell's equations which describe how electricity and magnetism work. Working through his equations he noticed that they implied that electromagnetic waves (in a vacuum) should travel at a constant speed.

   When he plugged in the various electrical and magnetic constants that had been previously carefully measured by experiment he found that within the margin of error of the experiments his calculated speed exactly matched the experimentally measured speed of light. He guessed and said that because of this coincidence that light was an electromagnetic wave.

   By assuming that this was correct great inroads were made in physics, including quantum mechanics and relativity.

   This and later experiments proved this hypothesis to be true. They started in radio, where a conductor has changing electricity producing an obvious electromagnetic wave, then on to microwave which is the same thing but changing at a faster rate, all the way up to infrared and now visible light and beyond into ultraviolet and xrays.

They are essentially the same thing. Solar radiation from the sun is made up of two components: (1) direct solar raidation; and (2) diffuse solar radiation. Global radiation refers to the sum of direct and diffuse fractions.

In the spectrum of electromagnetic radiation the wave property that changes is the frequency. So for example xrays have higher frequency then blue light which has higher frequency then red light which has higher frequency then radio waves etc.

James Maxwell was able to show that a vibrating charge would result in the propagation of an electromagnetic wave that would travel with velocity that "just happened" to be the speed of light. Since that time, repeated tests have shown that every prediction resulting from the idea that radio waves, light waves, and x-rays (amongst others) are examples of this EM wave have turned out to be correct.

Light is considered to be an EM wave because every test of that statement has given a positive answer.

That is, until, quantum theorists were able to show that light travels in discrete chunks of energy now called "photons."

Electromagnetic radiation is a very broad concept. If you look up 'electromagnetic spectrum', you will see that it is radio waves, infrared, visible light, ultraviolet, x-rays, gammas rays, etc. So, what are the uses?

Well radio waves are used for radios and other wireless communication like Wi-fi. This is pretty simple to figure out the uses and dangers (if any).

Infrared lights are used in many areas for different things. Your TV remote uses infrared. It's used for thermal imaging. It's used the sciences all the time. It's not particularly harmful either.

And visible light? I don't have to go into detail for this (if I should, you have a bigger problem).

UV light can be harmful, but many new technologies are making use of it. For the most part, it can be damaging to eyes and skin for long exposures and intense sources.

Microwaves. Microwaves are electromagnetic radiation too. Obviously, we are familiar with the conveniences of a household microwaves. These can be harmful because they are absorbed by water easily.

X-Rays and Gamma rays are used in medical sciences a lot as well as cutting edge physics experiments, particularly with astrophysics. These types of electromagnetic radiation are very high energy and can disrupt chemical bonds. This is mostly of concern with us because it can damage DNA and cause mutations and other carcinogenic effects.

Space wave propagation refers to the transmission of electromagnetic waves through free space without reflection or refraction. Two examples of communication systems that use space wave mode are satellite communication systems, where signals are transmitted between ground stations and satellites in orbit, and line-of-sight microwave communication systems, where signals are transmitted directly between two antennas within line of sight of each other.

Yes, infrared radiation can be blocked by materials that are opaque to it, such as metal foils, dense fabrics, and certain plastics. These materials absorb or reflect the infrared radiation, preventing it from passing through.

Yes, infrared radiation has a longer wavelength than visible light. Infrared radiation has wavelengths longer than those of visible light, ranging from about 0.7 micrometers (μm) to 1 millimeter (mm), while visible light ranges from about 0.4 to 0.7 micrometers (μm).

No, LED stands for light-emitting diode, which can produce a range of colors depending on the materials used in the diode. While some LEDs emit a single color (monochromatic), many are designed to emit multiple colors.

The first modern semiconductor diode was made with germanium. These diodes were invented in ww2 for RADAR.

But before that semiconductor diodes were made with galena (lead sulfide), copper oxide, and selenium. I have no idea which was "first".

The electromagnetic spectrum is called a spectrum because it consists of a range of electromagnetic waves or radiation, each with a unique wavelength and frequency. When these waves are arranged in order of their wavelengths, they form a continuous spectrum of different colors and energies.

Exit radiation refers to the electromagnetic radiation emitted from a material after an external stimulus, such as light or heat, is applied. This radiation can provide valuable information about the material's properties, structure, or composition. Exit radiation is commonly used in various scientific fields, including spectroscopy and materials science, for analysis and characterization purposes.

No, an object not moving relative to Earth is not a blue shifted object. With no relative motion, an object will not be subject to Doppler effect and will not red or blue shift. For an object to be blue shifted, the distance between the object and Earth must be decreasing. The object must be closing on Earth or vice versa.

No difference at all. Radio waves are one of many types of electromagnetic waves.

Wien's law is limited in that it is only accurate for objects that behave like blackbodies, meaning they absorb and radiate all incident energy equally. It also applies only to idealized objects that emit radiation in a perfect thermal equilibrium. Real-world objects may deviate from these ideal conditions, leading to inaccuracies in predictions made using Wien's law.

For pretty much the same reason that stars do. It's an optical illusion caused by the bending of light through a turbulent and hazy atmosphere.

If the unevenly-heated air between you and the streetlights happens to contain a mix of smoke, dust and water vapor, then the churning particles and droplets will act like tiny mirrors, shadows and lenses. This chaotic mix will distort the light rays passing through it, causing faraway light sources to appear to flicker or twinkle.

As you move closer to the light, the number of photons reaching your eyes rapidly increases. This tends to average out the apparent intensity of the light, making the twinkling effect 'magically' disappear. (This is also the same way ancient astronomers were able to tell planets from stars, by the way: the planets are close enough to Earth that it took a very turbulent sky indeed to make them appear to twinkle at all.)

Permanent magnets have a magnetic field around them. This field is an "area" of force, and the force is derived directly from the uniform motion of a large number of electrons in the ferromagnetic material. Moving electrons generate a tiny magnetic field around their path of travel, and this is the basis of the magnetic force. The "blocks" of atoms that have uniformly moving electrons are called magnetic domains. The aligned domains allow an "over all" magnetic field to be detected and even used by an investigator. The field will interact with ferromagnetic material to attract it, or will, when moved "past" any conductor, induce a voltage in that conductor.

A pair of magnets will attract or repel, depending on how they are held or placed. The magnetic field of each one will interact with the field of the other, and the lines of force will push or pull, as suggested.

Electromagnetic Waves do not require a medium, or matter to move through, to transfer waves. This includes radiowaves, microwaves, infared waves, visible light waves, Ultraviolet waves, X-rays, and gamma rays.

Any charged particle has an electric field surrounding it. If it oscillates, the electric field will continuously change, resulting in the production of a magnetic field, which is in phase with the electric field. But these two fields are perpendicular to each other. These two "oscillating fields" come together to form electromagnetic waves.

it protects all your internal organs from radiation by blocking the dangerous radiation, by producing sweat to protect against heat, has sensory receptors to tell you when you are in danger, and produce vitamin D from absorption of radiation