An isotope of a chemical element is an atom that has the same number of protons (this also means this atom has the same atomic number) and electrons, but has a different numbers on neutrons. The isotope is radioactive if it has too many neutrons in the nucleus and because of this the isotope is unstable.
The half-life of a radioactive isotope is a time period. When the isotope is at the end of the period it's weight will be the half of the starter weight.
The difference between count rate and activity of a radioactive sample is simply geometry - geometry as in the ratio of disintegrations versus observed counts.
It is true that activity is proportional to activity. One curie is defined as 3.7x1010 disintegrations per second (DPS), or one microcurie is more commonly defined as 2.2x106 disintegrations per minute (DPM). The problem is that not all of the disintegrations get counted. After all, the detector does not completely surround the source and, even if it did, still not all of the disintegrations will be counted.
During calibration, a known activity is presented to the detector in a known geometry, and the count rate is measured. Lets say that 0.01 microcurie yields 1x104 counts per minute. We would say, then, that the instrument's absolute efficiency is 0.45%, which is the ratio of 1x104 over 2.2x106. If you then measured an unknown activity and got 5x103 counts per minute, you could reasonable assume that the sample was 0.005 microcuries.
These number are all examples, "picked out of the air", to illustrate the principle. Actual detector design and geometry is a complex science and other factors, such as emergy absorbtion, pulse nullification, and linear vs avalanche mode, just to name a few, factor into the proper design and calibration of a detector.
Count Rate: Counts for radioactive emissions for a given period of time.
Half-life: Time it takes for half a given radioisotope to decay.
Serum half life is the calculated duration of time for a serum level of a compound to be reduced to half its initial value.
Yes, DNA does have a shelf life. It has a shelf life of about four years if it is properly preserved.
The shelf life is determined by the brewer and should be printed on the label.
Plutonium-238 has 144 neutrons, plutonium-240 has 146 neutrons. Atomic mass and half life are also different.
nothing
4 days
No half is a game. Shelf life? Then yes varies with temp and humidity
Yes Ambien 10 mg tablets have a shelf life a shelf life of about two and a half years. I have a bottle which was prescribed in July 2002 with an expiry date of Dec 2004.
According to the Gatorade website-9 months
Serum half life is the calculated duration of time for a serum level of a compound to be reduced to half its initial value.
The shelf life for this battery is between 8-10 years if it is unused. Most batteries have a shelf life of 5-10 years unused. So the choice is yours my friend.
Refrigerate them between uses.
A sponge cake is soft and is suitable for flat cakes, also it has a shelf life of about two days. A Madeira cake is a firmer more textured cake, suitable for cake sculptures and has a shelf life of up to two weeks!
Half Life Source is a direct port of the original to Valve's source engine meaning that like Half Life it is a science fiction first person shooter. The only difference between it and the original Half Life being slightly improved graphics.
If this question means to say, what is the difference between a rusk and a biscuit, the answer is - a rusk is generally a twice-baked biscuit. Dry, for a long shelf life.
what is the difference between a life lease and a life estate
Most 9-volt batteries have an estimated shelf life of up to ten years. At the minimum, they will have a shelf life of four years. Most packages of 9-volt batteries will claim a shelf life of somewhere between seven and ten years.