the dog ate the bacon
many. one example is lead-214 with a halflife of 26.8 minutes.
halflife
The primary source of radioactivity in the human body is Carbon-14. However the level of Carbon-14 remains constant in the body as the human body is in equilibrium with the atmosphere as long as the body is alive. Therefor there is no halflife until the body dies; then it matches the halflife of Carbon-14.
my grandma
no, halflife is a constant for each isotope's decay process.
To determine the half-life of the substance, you can use the fact that after one half-life, the substance will be reduced to half of its original amount. In this case, after 40 days, the substance is reduced to one sixteenth of its original amount, which represents 4 half-lives (since 1/2^4 = 1/16). Thus, each half-life of this substance is 10 days.
The basic idea is to compare the abundance of a naturally occurring radioactive isotope within a material to the abundance of its decay products; it is known how fast the radioactive isotope decays.
okay
Half-life is the time it takes for one half of a certain type of atom (isotope) to decay. The amount of time varies a lot between different isotopes; in some cases it may be a fraction of a second, in another, it may be billions of years.
Hydrogen has three isotopes: protium (1H), deuterium (2H), and tritium (3H). Protium is the most abundant and consists of one proton and one electron. Deuterium contains one proton, one neutron, and one electron. Tritium has one proton, two neutrons, and one electron.
Illadelph Halflife was created on 1996-09-24.
Half-life is the time it takes for one half of the radioactive material to decay. It is logarithmic, so after two half-lives, one quarter remains - then one eighth - etc.