Consider modern microwave oven used in kitchens. Are the microwaves ejected to heat water and food harmful to the human body? What is the Q in the calculation or REM? Answers Electron excitement. An electron is excited to a higher energy level. When it falls, it releases a packet of energy in the form of a photon.
Secondary ionization. The ejection of the second electron was caused by another electron, as opposed to another charged particle or radiating ray. Primary ionization. The electron was ejected by a charged particle or ray. Ionizing radiation describes atoms becoming ionized to ions. During ionizing radiation, an electron is ejected off the atom, causing the atom to lose an electron and become ionized. Non-ionizing radiation is generally caused by excitation of electrons.
When a particle or electromagnetic ray does not have sufficient energy to completely knock an electron off an atom, it can instead excite the electron to go to a higher energy level. When the electron falls, it emits photons of energy.
Radiation can ionize atoms, but it can also mutant molecules by ionizing atoms. It can affect the structure of a cell by debilitating organelles or other cellular functions, but its most damaging effect is on DNA. DNA mutations arising from irradiation can cause cancer, or otherwise kill the cell. Although there are many myths concerning microwave radiation, microwaves fall under "non-ionizing" radiation and hence does not cause any of the effects that ionizing radiation causes, such as cancer.
A microwave oven is also designed to minimise microwaves escaping outside of the oven by using metal to absorb the microwaves. This is why the door of the microwave oven is not transparent; it is lined with strategically placed metal atoms for maximum absorbing efficiency. Q is the constant that is used depending on what radioactive particle you are calculating. Gamma rays are often emitted along with alpha or beta particles during radioactive decay. Gamma rays are a radiation hazard for the entire body.
They can easily penetrate barriers that can stop alpha and beta particles, such as skin and clothing. Gamma rays have so much penetrating power that several inches of a dense material like lead, or even a few feet of concrete may be required to stop them. Gamma rays can pass completely through the human body; as they pass through, they can cause ionizations that damage tissue and DNA.
Because of their use in medicine, almost everyone has heard of x-rays. X-rays are similar to gamma rays in that they are photons of pure energy. X-rays and gamma rays have the same basic properties but come from different parts of the atom. X-rays are emitted from processes outside the nucleus, but gamma rays originate inside the nucleus. They also are generally lower in energy and, therefore less penetrating than gamma rays. X-rays can be produced naturally or by machines using electricity. Literally thousands of x-ray machines are used daily in medicine.
Computerized tomography, commonly known as a CT or CAT scan, uses special x-ray equipment to make detailed images of bones and soft tissue in the body. Medical x-rays are the single largest source of man-made radiation exposure.
Learn more about radiation sources and doses. X-rays are also used in industry for inspections and process controls. Elements in the periodic table can take on several forms. However, very high doses of radiation can kill the cell completely. We use this property of radiation to kill cancer cells, and also harmful bacteria and other micro-organisms. The hazard symbol is shown on containers of radioactive substances to warn of the danger. Radiation Protection: Health Effects. Accessed at www.
National Research Council of the National Academies. American Cancer Society medical information is copyrighted material. For reprint requests, please see our Content Usage Policy. Download this topic [PDF]. Radiation can also lead to infertility problems getting pregnant or fathering children Lower doses of radiation, such as from imaging tests are not known to cause short-term health problems.
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