d. A roentgen is a unit of radiation dose that produces one electrostatic
unit of electricity per cubic centimeter of dry air at 0 °C and 1 atm
pressure.
2. Decay Pattern (of Uranium-238) and Half-Life:

Common Student Misconceptions

                                                                  1. “Irradiated food is radioactive.”

                                                                                                 Although some foods have an extended shelf-life after
                                                                                                 radiation with gamma  rays, irradiation only kills
                                                                                                 the microorganisms in the food. This process does
                                                                                                 not make the food radioactive.

                                                                  2. “All radiation is harmful.”

                                                                                                  The physical harm caused by radiation varies greatly,
                                                                                                  depending on the quantity received, what type it is
                                                                                                  (gamma rays can be more harmful, in general, than
                                                                                                  alpha particles), whether the radiation is internal or
                                                                                                  external to the body, etc. (see the tables in the
                                                                                                  Appendix for additional comparisons).

                                                                  3. “All radiation is man-made.”

                                                                                                  Most radiation to which humans are exposed is natural
                                                                                                  radiation from cosmic rays or from naturally occurring
                                                                                                  radioisotopes.
 
 
 
 

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