Course Hero Logo

Basic Concepts of Radiation.pdf - Lecture-2 M.Sc 2nd...

Course Hero uses AI to attempt to automatically extract content from documents to surface to you and others so you can study better, e.g., in search results, to enrich docs, and more. This preview shows page 1 - 7 out of 31 pages.

Lecture-2M.Sc 2nd Semester(Environmental Microbiology)Paper EM-202:Microbial physiology and adaptationUnit IV:Basic Concepts of Radiation
RadiationRadiation is a process in which energetic particles or energeticwaves travel through a medium or space.There is mainly two type of radiation. i.e.Ionizing Radiation.Non Ionizing Radiation.The word radiation is often colloquially used in reference toA.Ionizing radiation(radiation having sufficient energy to ionizean atom) andB.Non-ionizing radiation(radio waves, heat or visible light).All life is dependent on small doses of electromagnetic radiation.For example,photosynthesis and vision use the suns radiation.Natural radiation was the only source of human exposure until the latter part ofthe nineteenth century when Thomas Edison invented the electric light. Mostnatural radiation of significance occurs in a small part of the lowermost frequencyspectrum (electrostatic to about 5 kHz) and in the uppermost part of the spectrum(above 1013 Hz).
The sun emits radiation composed of high energy infrared radiation,visiblelight,andultravioletradiationcollectivelyknownasshortwave radiation (SW)The earth emits radiation composed of lower energy infraredradiation collectively known as long-wave radiation (LW)Ionizing radiation is far more harmful to living organisms per unitof energy deposited than non-ionizing radiation, since the ions thatare produced by ionizing radiation, even at low radiation powers,have the potential to cause DNA damage.Non-ionizing radiation is harmful to organisms only in proportionto the thermal energy deposited, and is conventionally consideredharmlessatlowpowerswhichdonotproducesignificanttemperature rise.Ionizing and non-ionizing radiation can be harmful to organism andcan result in changes to the natural environment.
Ionizing RadiationIt is a type of radiation that is able to disrupt atoms and moleculeson which they pass through, giving rise to ions and free radicals.It has enough energy to eject one or more electrons from theatoms or molecules in the irradiated medium.Ionizing radiation is produced by unstable atoms. Unstable atomsdiffer from stable atoms because they have an excess of energyand mass.Each ionization releases approximately 33 electron volts (eV) ofenergy.Materialsurroundingtheatomabsorbstheenergy.Compared to other types of radiation that may be absorbed,ionizing radiation deposits a large amount of energy into a smallarea. In fact, the 33 eV from one ionization is more than enoughenergy to disrupt the chemical bond between two carbon atoms.Allionizingradiationiscapable,directlyorindirectly,ofremoving electrons from most molecules.
Ionizing Radiation cont.Higher frequency ultraviolet radiation begins to have enoughenergy to break chemical bonds. X-ray and gamma ray radiation,which are at the upper end of magnetic radiation have very highfrequency in the range of 100 billion billion Hertz and very shortwavelengths 1 million millionth of a meter. Radiation in this rangehas extremely high energy. It has enough energy to strip offelectrons or, in the case of very high-energy radiation, break up thenucleus of atoms.

Upload your study docs or become a

Course Hero member to access this document

Upload your study docs or become a

Course Hero member to access this document

End of preview. Want to read all 31 pages?

Upload your study docs or become a

Course Hero member to access this document

Term
Spring
Professor
NoProfessor
Tags
Radioactive Decay, Test, Electromagnetic spectrum, Ionizing radiation, GAMMA

Newly uploaded documents

Show More

Newly uploaded documents

Show More

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture