Electromagnetic Radiation

Electromagnetic (EM) radiation is the energy transmitted through space or a material medium in the form of electromagnetic waves. The frequency range of such waves is tremendous, and is shown by the electromagnetic spectrum. These waves include radio waves, microwaves, infrared waves, visible light waves, ultraviolet (UV) waves, X-rays, and gamma rays.

6,782 Questions
Electromagnetic Radiation
Waves Vibrations and Oscillations

What describes a difference between electromagnetic and mechanical waves?

mechanical waves need a medium to travel through, electromagnetic waves do not. Electromagnetic waves can travel through space, mechanical waves can not.

:P
Electromagnetic waves do not require a medium, but mechanical waves do.

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Science
Physics
Medical Technologies
Electromagnetic Radiation
X-Ray
Visible Light Spectrum

Which of the following have the highest frequency in the electromagnetic spectrum x-rays infrared waves ultraviolet rays or visible light?

X-rays have the highest frequency in the electromagnetic spectrum.

121314
Physics
Electromagnetic Radiation

How are the energy and wavelength of electromagnetic radiation related?

The energy of one photon is given by its frequency X planck's constant Its frequency is given by the speed of light divided by the wavelength.

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Physics
Chemistry
Nuclear Physics
Electromagnetic Radiation

Which is not true of beta radiation?

It is the heaviest of the three types.

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Inventions
Electromagnetic Radiation
Microwave Ovens

When was the microwave invented?

MICROWAVES

Microwaves are electromagnetic waves with wavelengths from 1 mm to 1 m. The existence of electromagnetic waves was predicted in 1864 by James Maxwell. Hertz was the first person to demonstrate the existence of electromagnetic waves in 1888. In 1894, Bose demonstrated the use of high frequency waves by generating microwaves to explode gunpowder and ring a bell at a distance.

Various uses for microwaves have been developed since then, including communication systems, radar systems, speed limit enforcement, medical imaging, cooking, and weaponry.

MICROWAVE OVENS

The patent for the first microwave oven was filed on October 8th, 1945. The idea came as a result of radar/magnetron waves melting a chocolate bar in the pocket of Percy Spencer, an engineer working for Raytheon. The company began selling the first commercial microwave oven, the "Radarange," in 1947.

MICROWAVES FROM OUTER SPACE

However, all of mankind's discoveries and inventions regarding microwaves pale into insignificence when one considers that microwaves are bombarding us from the sun and the universe on a daily basis! [cosmic background microwave radiation] And they have been doing so for countless eons! So microwaves were invented, um, ...a very long time ago!

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i think this in unrevlent and the answer is simply 1945.

For more information, see 'Related links' below this box.

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Chemistry
Electromagnetic Radiation

A particular sensitizer can absorb photons of one wavelength and release photons of a longer wavelength Why must the radiation be at a longer wavelength?

First, consider the relationship between wavelength and energy and reformulate the premise in terms of energy. Then, study fluorescence, the process in which a molecule absorbs a photon and releases a subsequent photon at a longer wavelength.

In fluorescence, energy must be conserved. The total energy absorbed must be equal to the total energy released by the excited molecule (sensitizer). The question is asking, for example, if a sensitizer absorbs a photon with energy of 3 eV and releases a photon of 2.5 eV, where did the missing 0.5 eV go?

This question comes directly from the laboratory manual for the introductory chemistry courses at the University of Alabama. For those students attempting to find an easy answer without putting forth any effort, i.e. cheat, you'll have to look elsewhere.

- Mr. E.

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Electromagnetic Radiation

How are ultraviolet radiation and microwave radiation the same?

I had this same question on my homework, but I don't know how they are the SAME. I do know how they are different though. ultraviolet radiation begins at the short wavelegth then overlaps to the long x-ray wavelength and the microwave radiation starts at the longest wavelength then goes to the shortest.

sorry i couldn't really answer your question though

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Cooking Equipment
Physics
Electromagnetic Radiation

How does a microwave oven get food hot?

Microwaves are electromagnetic waves. The microwave oven generates these and directs them into the cavity where food is placed. The microwaves act on the water molecules in food, and because the water molecules are polar, they will attempt to orient themselves according to the passing microwaves. Because the microwaves are waves, they have crests and troughs, and these will cause the water molecules to "flip" continuously. This generates heat, and the heat warms the food.

151617
Science
Electromagnetic Radiation
Spectroscopy
Visible Light Spectrum

What is the electromagnetic spectrum?

The electromagnetic (EM) spectrum is the entire range of frequencies that electromagnetic radiation can have. The EM spectrum is divided into sections based on the common characteristics that certain frequency ranges have. These sections are, in order from low to high frequency, radio waves, microwaves, infrared waves, visible light (which from low to high frequency is further divided into red, orange, yellow, green, blue, indigo, and violet), ultraviolet waves, X-rays, and gamma rays. You can think of the EM spectrum as an invisible rainbow with visible light being a small part of it. And, like a rainbow, the edges of the divided sections are blurry; i.e. there is no exact frequency where one can say, for example, that this wave is no longer an X-ray, but is instead a gamma ray.

it is waves of light in order of their wavelengths and frequencies

APEX: A chart of frequencies of light waves.

525354
Physics
Electromagnetic Radiation
Visible Light Spectrum

Which has the lowest frequency in the electromagnetic spectrum microwaves radio waves visible light or gamma rays?

Radio waves have the lowest frequency in all of the electromagnetic spectrum. The next higher frequency energy is microwave, visible light including ultraviolet, infrared, X-ray, then gamma ray

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Albert Einstein
Electromagnetic Radiation
Quantum Mechanics

How did Albert Einstein explain the photoelectric effect?

Apex

Light is made of photons.

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Electricity and Magnetism
Electromagnetic Radiation
Waves Vibrations and Oscillations

How are electromagnetic waves different from mechanical waves?

Electromagnetic waves can travel through space or a medium while mechanical waves need matter to transfer energy.

Apex- They don't require a medium to travel through.

151617
Physics
Medical Technologies
Electromagnetic Radiation
Radio
X-Ray

What has the longest wave length infrared radiation radio wave ultraviolet radiation or X-ray radiation?

Listed from longest to shortest wave length: * radio waves * infrared radiation * ultraviolet radiation * x-ray radiation

91011
Physics
Electromagnetic Radiation

What is the speed of infrared light?

All electromagnetic waves travel at the same speed, in vacuum - a speed known as the "speed of light". About 300,000 km/sec.

567
Physics
Electromagnetic Radiation

How does the frequency of microwave radiation compare with infrared radiation?

Microwave is lower frequency.

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Electromagnetic Radiation

What is a curved piece of glass or other transparent material that is used to refract light called?

It's called a concave lens.

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Colors
Electromagnetic Radiation

What color does red and cyan make?

121314
Electromagnetic Radiation

What does an electromagnetic spectrum refer to?

A range of wavelengths of light that increases from one end to the other

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Electricity and Magnetism
Electromagnetic Radiation
Waves Vibrations and Oscillations

Is a towel waving a mechanical wave or electromagnetic wave?

-- There is nothing electric or magnetic about a towel.

-- It doesn't use batteries or photovoltaic cells, it doesn't attract charged objects,

and when you hang it up and it's free to turn, it shows no tendency to point north.

-- It doesn't glow in the dark, shock you when you touch it, or pick up radio signals.

-- It doesn't generate electric current, make cross-hatch lines on the TV picture,

or heat a piece of meatloaf wrapped in it.

-- If you pick it up with your hand and wave it with your arm, then it waves.

-- This all sounds pretty mechanical.

012
Physics
Chemistry
Global Warming
Electromagnetic Radiation

What are the sources of infrared radiation?

Heat sources.

(or more generally, sources of electromagnetic radiation)

It is so far undenied (and "functions") that infrared is an electromagnetic radiation with a slightly higher wavelength = slightly lower frequency than visible light.

(search key words: infrared, frequency, wavelength, source)

Infrared propagates in vacuum as well as in the atmosphere.

Infrared penetrates slightly deeper into material than visible light (cf. "light therapy effects") or ultraviolet (which deposits its energy at the surface, causing for example a sun tan or skin cancer) and feels "warm".

111213
Physics
Nuclear Physics
Electromagnetic Radiation

What is the difference between a microwave photon and a gamma ray photon?

Both a microwave photon and a gamma ray photon are examples of electromagnetic energy. The difference is that a gamma ray photon is of a much higher frequency than a microwave photon. This also means that the gamma ray has a much shorter wavelength, and a much higher energy.

Microwaves are essentially "high energy radio waves" which have a frequency range below that of visible light. As we climb the frequency scale in the electromagnetic spectrum, it goes microwaves, infrared light, visible light, ultraviolet light, X-rays and gamma rays. You can see from that layout that gamma ray photons are well above microwaves. In fact, gamma rays, which originate in atomic nuclei or in nuclear processes, are at the very top of the electromagnetic spectrum.

111213
Electromagnetic Radiation

What does a electromagnetic spectrum contain of?

what does an electromagnetic spectrum consist of

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Electromagnetic Radiation

What energy does the electromagnetic spectrum make?

the energy that makes the electromagnetic spectrum is electromagnetic radiation

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Electromagnetic Radiation
Visible Light Spectrum

How is visible light different from other forms of electromagnetic radiation?

It's visible, whereas the others are not.

91011
Physics
Electromagnetic Radiation
Waves Vibrations and Oscillations

Does shorter wavelength mean higher frequency?

Yes.

The product of [ (wavelength) times (frequency) ] gives the speed of the wave, which is always the same.

Since the product of the two quantities always produces the same number, you can see that if one increases,
the other one has to decrease.

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