What Is Radioactivity

What is radioactivity Indicate whether you agree or disagree with the following statement, and indicate your reasons Henri Becqueiel s discovery of radioactivity shows that the atom is not indivisible, as had been believed for so long. 

The problems encountered in the USA over the Below Regulatory Concern policy were mentioned earlier. For similar reasons a policy of zoning in the French nuclear industry is being proposed, in which some areas are declared as containing radioactive materials and others are defined as being free from radioactive materials. The disposal of materials and structures within the radioactive zones will be managed without release from the zones, with the intention of avoiding the need for exemption and clearance. However, even with this approach it will be necessary to define what is "radioactive" and what is not. 

What is radioactivity What does it mean for an atom to be radioactive ... 

The activity in a 10.00-mL sample of radioactive wastewater containing fgSr was found to be 9.07 X 10 disintegrations/s. What is the molar concentration of 3gSr in the sample The half-life for fgSr is 28.1 years. 

Table 13.1 provides a list of several isotopes commonly used as tracers. The half-lives for these isotopes also are listed. What is the rate constant for the radioactive decay of each isotope ... 

Radioactivity. Methods based on the measurement of radioactivity belong to the realm of radiochemistry and may involve measurement of the intensity of the radiation from a naturally radioactive material measurement of induced radioactivity arising from exposure of the sample under investigation to a neutron source (activation analysis) or the application of what is known as the isotope dilution technique. 

A radioactive sample contains 3.25 X 1018 atoms of a nuclide that decays at a rate of 3.4 X 1013 disintegrations per 15 min. (a) What percentage of the nuclide will have decayed after 150 d (b) How many atoms of the nuclide will remain in the sample (c) What is the half-life of the nuclide ... 

The basis of most environmental issues is pollution. But what is pollution Keep in mind that with very minor exceptions, virtually all of the atoms in the solid, liquid, and gaseous parts of the Earth have been a part of the planet for all of its approximately 4.5 billion years of existence. Very few of these atoms have changed (i.e., by radioactive decay) or departed to space. 

C22-0051. A radioactive nuclide of mass number 94 has been prepared by neutron bombardment. If 4.7 pg of this nuclide registers 20 counts per minute on a radioactivity counter, what is the half-life of this nuclide ... 

C22-0097. What is the shelf life of a radioactive nuclide with a half-life of 14.6 days if it loses its usefulness when less than 15% of the radioactivity remains ... 

C22-0114. The amount of radioactive carbon in any once-living sample eventually drops too low for accurate dating. This detection limit is about 0.03/g min, whereas fresh samples exhibit a count rate of 15.3/g min. What is the upper limit for age determinations using carbon dating ... 

Suppose the initial number of nuclei of a radioactive nuclide is N0, and that the half-life is T. Then the amount of parent nuclei remaining at a time t can be written as Nx = NQ( /2)(tlT>. This relationship is called the radioactive decay equation. What is the number of daughter nuclei present at time t, expressed in terms of N0 and Nx ... 

The work described here was undertaken to determine what happens to the sulfur that is volatilized, and what is the source of the hydrogen sulfide, sulfur dioxide, and sulfate. The products formed by lemons treated with elemental sulfur were employed in radioactive form for the treatment of other lemons. 

The structure of some isotopes, generally referred to as stable isotopes, is immutable (see Textbox 13). Others, known as radioactive isotopes or radioisotopes, are unstable in time they undergo what is known as... 

What is the difference between radioactive decay processes and other types of nuclear reactions ... 

Processes in nature correspond generally only in a first approximation to what is postulated in the principles of dating methods. An exception is radioactive decay which is almost independent of variations in the environmental conditions, since energy differences are involved which are large compared to differences of thermal excitation in the environment. This is in contrast to chemical and physical processes which do depend on environmental parameters such as temperature. An example showing... 

A hollandite structure phase containing Ba, Ti, Al, and O is fabricated with the aim of immobilizing radioactive nuclides, (a) What is the formula of the hollandite (b) It is desired to replace 10% of the Ba with radioactive K. What would the formula of the new phase be (c) It is desired to replace 35% of the Ba with radioactive Sr. What would the formula of the new phase be (d) It is desired to replace 17% of the Ba with radioactive La. What would the formula of the new phase be ... 

But many people talk emotionally of radioactivity because radioactive materials are so poisonous , and one of the clinching arguments given to explain why radioactivity is undesirable is that radioactive materials have long half-lives . What is a half-life And why is this facet of their behaviour important And, for that matter, is it true that radioactive materials are poisonous ... 

A radioisotope sample with a half-life of 10 days contains 250 mCi radioactivity. What is the radioactivity of the sample after 23 days ... 

A 10 mCi dose is ordered and the radiopharmaceutical activity concentration is presently 16 mCi/mL. What is the quantity to be dispensed to provide the necessary radioactivity ... 

Problem 1.13 A radioactive element gives 2000 counts per min at a given time. After one hour, counts were found to be 750 per min. What is half-life of the element ... 

An atom of 23 U undergoes radioactive decay by a emission. What is the product nuclide ... 

Metabolism. There is a paucity of information on PCB metabolism in fish. With the exception of one study of one study (25) metabolites of PCBs in fish have not been identified other than to say they were more polar than the parent compound (26,27,28,29). Also while effect of degree of chlorination on PCB metabolism in fish has been studied (26) effect of chlorine position has not. What is known is that fish in general metabolize PCBs at a slow rate in comparison to mammalian species (29,30,31) and that rate of metabolism appears to be inversely related to degree of chlorination (20,26). Table IV shows percentage of radioactivity... 

The melting point, boiling point, and density of seaborgium are unknown. What is known is that its isotopes are radioactive metals with short half-lives and that these isotopes decay by fission and alpha emissions. 

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