Question:
CA [mm] 4.40 3.55 2.98 2.57 2.26 2.01 1.81 1.65
t [s] 0 100 200 300 400 500 600 700
Use the method of half-life to find the order and the constant of speed.

1) Radioisotopes such as aluminum -26, which is believed to have been present in the solar system when earth was formed but can no longer be detected, are known as extinct radionuclides. The half-life for the decay of aluminum -26 is 7.20 x 10 ^5 years.
How many years did it take for 99.99% of the aluminum -26 to decay? If

1.) (A) DEFECTS
Metals yield at a stress much lower than those calculated on the basis of their bond strength alone. This is explained by the presence of defects. Identify the principal defects responsible for this observation.
a.) Grain Boundaries
b.) Interstitial Metal Atoms
c.) Vacancies
d.) Dislocations
1.) (B) DEF

Why are scientists spending a great deal of effort to build a fusion reactor even though it would operate at a very high temperature that could be difficult to reach and maintain?
Radioisotopes in nuclear medicine are desirable to have shorter half-lives. Why?

1. A source has a half-life of 12 hours and an initial activity of 10mCi. After 4 days what is its activity?
2. Calculate the % of activity remaining in a source after 10 halflives.
3. a. A radionuclide decays 1% in one day. Calculate the half life.
b. A radionuclide decays 70% in one day. Calculate the half life.
4. A

Three radioactive sources each have activities of 1.0 micro Curies (Ci) at t=0. Their halflives are 1 sec, 1 hour and 1 day respectively
a.) how many radioactive nuclei are present at each source when t=0
b.)how many nuclei of each source decay between t=0 and t=1sec
c.)how many nuclei of each source decay between t=0

The equation for radioactive decay is: N(t) = Noe-kt, where No is the initial number of radioactive atoms, N(t) is the number of radioactive atoms left after a time t, and k is the decay constant. The half-life of carbon 14 is about 5730 years.
Radioactive carbon dating makes the assumption that living things absorb carbon 14