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    Radioactive decay of a substance is modelled by:

     R = 1000e^{-ct} , c is a positive constant, t is the time in years and R is the number of atoms.

    It takes 5730 years for half of the substance to decay.

    Find c.

    Well I knosw t = 5730, but what is R? I know R = no. of atoms, but it doesnt say how many atoms there are when half of the substance has decayed, so is R = 1/2?

    I know how to solve it using logs, just need to know what R = !

    Please help!!

    Thanks
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    (Original post by Chemhistorian)
    Radioactive decay of a substance is modelled by:

     R = 1000e^{-ct} , c is a positive constant, t is the time in years and R is the number of atoms.

    It takes 5730 years for half of the substance to decay.

    Find c.

    Well I knosw t = 5730, but what is R? I know R = no. of atoms, but it doesnt say how many atoms there are when half of the substance has decayed, so is R = 1/2?

    I know how to solve it using logs, just need to know what R = !

    Please help!!

    Thanks
    What does the 1000 indicate? Once you realise this you'll know.
 
 
 
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