1000 particles of an unknown radioisotope decays to 472.37 particles in 50 days.(adsbygoogle = window.adsbygoogle || []).push({});

(a) What is the half-life of this substance?

Any problems that I had done previously, the half-life was given.

Any help will be greatly appreciated.

Well, I know a few things, but don't know if they apply to this problem:

The decay constant = .693/T base 1/2

t 1/2 = half-life

Time to decay to a single particle = LN(Nbase0)/decay constant

N = number of particles remaining at some elapsed time

Nbase0 = number of particles we started with

e = a symbol that represents the irrational number 2.718281828...

lambda = decay constant

x = elapsed time

The formula to determing how much of the substance will be remaining at any particular time is: N = Nbase0 e^-lambda x

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# Homework Help: Finding the half-life of an unknown substance

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