The radioactive nuclide _(27)^(55)Co has a half-life of 17.5 hours. What mass of _(27)^(55)Co remains from a 0.0100 gram sample after 24.0 hours have elapsed?
The half-life of _(26)^(59)Fe is 44.6 days. How long will it take for 95.0% of a sample of this nuclide to decay?
A sample of _(20)^(45)Ca, a \beta - emitter, has an activity of 0.1000\mu Ci. In 60.0 days, the activity of the sample has declined to 0.0775\mu Ci. What is the half-life of _(20)^(45)Ca ?
The half-life of tritium (hydrogen-3) is 12.3 years. If 48.0 milligrams of tritium is released from a nuclear power plant during course of an accident, what mass of this nuclide will remain after 12.3 years? After 49.2 years?
A sample of curium-243 was prepared. After 1.00 year, the activity of the sample had declined from 3012 disintegrations per second to 2921 disintegrations per second what is the half-life of the decay process?
A freshly isolated sample of ^(90)Y was found to have an activity of 9.8\times 10^(5) disintegrations per minute at 1.00Pm on December 3, 1992. At 2:15 PM on December 17,1992 , its activity was predetermined and found to be 2.6\times 10^(4) disintegrations per minute. Calculate thee half-life of ^(90)Y.
The carbon from the heartwood of a giant sequoia tree give 11_(6)^(14)C counts per minute per gram of carbon, whereas the wood from the outer portion of the tree gives 15_(6)^(14)C per minute per gram of carbon. How old is the tree? The half-life of _(6)^(14)C is 5730 years.
A wooden artifact from a Chinese temple has a ^(14)C activity of 24.9 counts per minute as compared with an activity of 32.5 counts per minute for a standard zero age. From the half-life for ^(14)C decay, 5715 years, determine the age of the artifact.