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Radiation

It’s actually well known that heat is a form of energy which transfers hotness from one point to the other. Its gets transfer from one point to another by three modes of which radiation is the one. The most common illustration for it is electromagnetic radiation. Light gets transferred in the form of electromagnetic radiation. Other examples are solar radiation, nuclear radiation etc.

Electromagnetic radiation is continuously emitted from all substances because of the molecular and atomic vibration accompanying the internal energy. The equilibrium state gives the internal energy proportional to the material temperature and that’s the reason we are not aware of these radiant energy which constantly surrounds us as our body can detect only some portions of the spectrum. Our eyes can detect light as they are very sensitive to changes in light occurring around us and our sensitive skin can detect heat radiation but unless these heat radiations is quite large we cannot sense it.

 

Types

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Radiation consists of wide range of energies which we see in electromagnetic spectrum. Basically they are classified as

1) Non-ionizing radiation
2) Ionizing radiation

The non ionizing radiation consists of alpha particles, beta particles and gamma particles whereas ionizing radiation consists of microwave radiation, infrared radiation and radio waves.

Nuclear Radiation

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As per the International Atomic Energy Agency a nuclear radiation is any incident that can cause consequences to nature, human life and facility significantly. Nuclear radiation is nothing but the energy released by elementary particles of atomic nucleus by the process of nuclear decay. It could be both beneficial or harmful depending upon which these are utilised. 

The nuclear radiation are of three types:
1) X rays
2) Beta rays
3) Gamma rays
X rays 

These are nothing but photons and have quite a few more energy than UV light but is less than gamma rays. The lower energy limit of these X rays is approximately around 10 eV while the higher limit is found to be around 100 KeV.

The atomic electrons are initially excited into higher energy states by primary electrons and once the ions get back to their lowest energy states or ground state they shed their excess energy in the form of X-rays. 

Larger the atom greater is the chance of absorbing an X ray photon as the energy difference between the electrons of the orbital. As far the application of X ray is concerned the soft tissues and bones with calcium deposit shows a difference in the manner in which atoms of tissues and bones absorb these energy rays. This difference in the absorption helps the physicians to identify and examine the bone structures.

Gamma Radiation

Being the smallest of the wavelengths and very high frequency, it has the most penetrating power and carries huge amount of energy. Produced by the neutrons and most energetic particles it is produced in a very hot zone especially the explosions of super nova, the neutron stars and black holes. It can also be observed during nuclear detonations and lightning.

The gamma rays are basically used in medicine fields to treat against cancer cells and could also be used as tracer material. These are also used in positron emission tomography. 
Alpha Radiation

These are emitted by heavy atoms of Uranium and plutonium and basically nothing but helium particles which makes them the most massive of the particle radiation. As it happen the alpha radiation causes very heavy damages to the living cells it comes across but since the frequency is just a few microns it fails to penetrate the epidermal cells. Although the radiation if taken into open wounds, swallowed or even inhaled can cause severe damage to the cells.

These are mainly found in the rocks and soils of minerals, smoke detectors or even nuclear detonations.

Beta Radiation

These are lighter than alpha particles and possess lower electrical charge comparatively. That also signifies that they will not cause as much damage but could enter up to one cm into a tissue layer. The radiation could be detected only to the skin and unless inhaled, exposed to open wounds or swallowed in its relatively harmless. These are found in natural potassium, rocks and soils and as C-14 and tritium in atmosphere.

Ionizing Radiation and Non-Ionizing Radiation

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Ionization radiation includes photons of electromagnetic radiation and accelerated particles of radiating elements and is expressed in terms of electron volt. These are energy that’s required to help extract electrons from atoms and molecules and in the process ionize them.

Almost all the atoms are stable but sometimes we come across unstable atom which radiate energy spontaneously or disintegrate into newer atoms and the excess of internal energy which is radiated off as gamma rays, alpha or beta particle and the process is termed as radioactive decay.

Non-ionizing radiation are basically series of energy waves which do not end up ionizing the surrounding. These are composed mainly of oscillating waves of electrical and magnetic fields moving at the speed of light. These are mainly the spectrum of visible light range, ultra-violet and infra-red, radio frequency and eve the microwave.

Black Body Radiation

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Any object which absorbs all the incident radiation falling on it until it radiates off the energy from it produced by the standing wave of the black body. The radiation does not depend upon the type of incident radiation and could be a classical example of a perfect emitter and absorber of radiation over a wide range of wavelength.The thermal energy radiation by a black body’s spectral distribution is dependent only on temperature.

The characteristics of black body radiation could be explained by several laws which govern the density and wavelength of spectral energy. Planck’s law of black body radiation, Wien’s displacement law and Boltzmann law are the ones which explains a lot about how black body radiation emission and frequency.

How Does Radiation Work?

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Radiation is the energy which travels in form of electromagnetic wave and or high speed particles. These could range from very high to very low Electromagnetic waves which again could be ionizing or non –ionizing. Radiation energy is mainly used for treating cancerous cells in the body. The radiation energy helps in damaging the DNA codons within the cancerous cells and hence restrains the cell growth.

Symbol & Units

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The International symbol for radiation is tri-foil which is highlighted in yellow background and drawn in black. This sign helps in warning people who are close to the radiation zone or are in vicinity to zones where radiation could be expected.

  

The international system of units which works for radiation measurement uses either gray (Gy) and or Sievert (Sv) while in countries like US the level of radiation doses are measured in roentgen(R) or rad.

1 Gy = 100 rad

Emf Radiation & Radiation Chart

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Electromagnetic field radiation are nothing but the radiation formed by electrical instruments in waves invisible to eyes. These are both electrical and magnetic in nature and could cause harm to living organisms with proximity to the electrical instruments.

Electrical Instruments  Proximity Damage 
Mobile Very high 
Television  High from 6 inches and reduces beyond 6 feet
Microwave oven High from 6 inches and reduces beyond 4 feet
Can opener   Very high from 6 inches and reduces from 4 feet

Radiation Detector & Use of Radiation

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The detectors used for radiation helps in converting the signals to electric current which identifies the very high energy particles produced by nuclear decay. They help in measuring the radiation and could be ionizing gaseous detectors or semiconductor detectors as well.

Radiation is used mainly for medical diagnosis and treatment of cancer. The use of X ray is imminent as far diagnosis is concerned for any kind of therapeutic uses. The use of photographic plates for any kind of therapy is now a routine process. Cancer detection and treatment is again a domain of radio therapy.

Radiation science is used for many academic research works and one has to apply nuclear science now to know and find solutions to environmental impact and topics related to archaeology and inbound rays from deep space.

Radiation science is widely used in industries as well for making precision tools, irradiation, making food safer from germs, and medical tools. The knowledge of radiation science makes it more viable to produce accurate user friendly final products. 

Radiation science also helps us to make rapid progress in nuclear science and harness the available nuclear resources to produce more nature friendly sustainable energy.

Examples

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Common examples of radiation could be sun bathing, sitting in front of hot oven, radiation from a glowing bulb etc. specifically the ionizing radiation could include solar radiation, X ray, cancer treatment by radiation and even security scanners used in airport terminals. The non-ionizing radiation could be just TV and radio speakers or frequencies that work for TV remotes etc.
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