The time required for half the atoms of a particular radioisotope to decay into another isotope . A specific half-life is a characteristic property of each radioisotope. Measured half-lives range from millionths of a second to billions of years, depending on the stability of the nucleus.
What is half-life and an example?
The quantity of radioactive nuclei at any given time will decrease to half as much in one half-life. For example, if there were 100g of Cf-251 in a sample at some time, after 800 years, there would be 50g of Cf-251 remaining. After another 800 years (1600 years total), there would only be 25g remaining.
What do we mean by half-life?
Half-life, in radioactivity, the interval of time required for one-half of the atomic nuclei of a radioactive sample to decay (change spontaneously into other nuclear species by emitting particles and energy), or, equivalently, the time interval required for the number of disintegrations per second of a radioactive ...
How does half-life work?
The half-life of a drug is an estimate of the period of time that it takes for the concentration or amount in the body of that drug to be reduced by exactly one half (50%). ... For example, if 100mg of a drug with a half-life of 60 minutes is taken, the following is estimated: 60 minutes after administration, 50mg remains.
What is the formula for calculating half-life?
Let N be the size of the population of the radioactive atoms at a given time t, dN be the amount by which it decreases in time dt. The rate of change is given as dN/dt = -λN , where λ is the decay constant.
Why is it called a half-life?
It's easy misinterpret half-life to mean “one half of the time it takes for whatever atoms you're looking at to decay,” but it actually means “ the length of time it takes for one half of the atoms you're looking at to decay .” The measurement is useful in radiometric dating, says Dee, because exponential decay means “it ...
What is the shortest half-life?
Hydrogen-7 ( about 23x10E-24) has the shortest half life.
What occurs during half-life?
What occurs during one half-life? Half of a daughter isotope undergoes radioactive decay to form a parent isotope . Half of a parent isotope undergoes radioactive decay to form a daughter isotope. All of a daughter isotope undergoes radioactive decay to form a parent isotope.
Which drug has the longest half-life?
However, there are numerous other drugs with very long half-life, examples are mefloquine 14–41 days (25), amiodarone 21–78 days (26), and oritavancin 393 h (27). Furthermore, what can be called “long half-life” is always relative to the length of the sampling period.
What does half-life of 12 hours mean?
3 This means that if you begin taking a medication with a half-life of 24 hours, after four days, or on the fifth day, the rate of intake of the drug will approximately equal the rate of elimination. If the half-life is 12 hours, you'll reach a steady state at the beginning of the third day (after 48 hours).
What does a drug's half-life mean?
The half-life of a drug is the time it takes for the amount of a drug's active substance in your body to reduce by half . This depends on how the body processes and gets rid of the drug. It can vary from a few hours to a few days, or sometimes weeks.
What made half-life so good?
The brilliance of Half-Life begins with its immersive storytelling . ... In this way, Half-Life is naturalistic, which was a revelation in 1998. The lack of cinematic cutaway scenes showed great faith in the world and the player, and deepened your relationship with the environment and the protagonist.
What is the purpose of half-life?
The half-life of an isotope is used to describe the rate at which the isotope will decay and give off radiation . Using the half-life, it is possible to predict the amount of radioactive material that will remain after a given amount of time.
Is half-life free forever?
To celebrate the upcoming launch of Half-Life: Alyx, Steam has announced all of the Half-Life games are going free to play! Hooray! The bad news is that the freebies won't be around forever , but hey, you can't have it all.
Which element has a half-life of 8 seconds?
The element with a half-life of only eight seconds is meitnerium . More precisely, it is the meitnerium-278 isotope that has a half-life of eight...
