sabre2th1
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I know -dN/dt = (lambda)N and that lambda is the decay constant. I also know that the larger the value for lambda, the faster the rate of decay but what does lambda actually represent?

Edit: I've got another question. If the count rate of a substance is 15 per minute then does that mean 15 atoms decay each minute?
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KeyFingot
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lambda is the probability of radioactive decay per unit time
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Cora Lindsay
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(Original post by sabre2th1)
I've got another question. If the count rate of a substance is 15 per minute then does that mean 15 atoms decay each minute?
No, though it is often taken to be the case in exam questions to simplify things.

First of all, your detector may not detect 100% of the radiation emissions; for example semiconductor gamma ray detectors can be as little as 1% efficient (ie detect only one photon in 100).

Second, not all decays necessarily give the particle or photon you are looking for. For example, only 35% of Am-241 alpha decays are accompanied by a gamma ray at 59.5 keV. So even if you have a 100% efficient gamma detector, 15 gamma counts per second would mean approximately 43 Am decay events per second.
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