Refer to figure 13-2 and determine how much parent material will be left after five half-lives
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Explanation: This is a type of radioactive decay and all the radioactive process follow first order kinetics.

Half life is the time required to decompose half of the reactants. thus after every half life the reactant will decompose to half of its present value.

Now, to calculate the number of half lives, we use the formula:

where,

a = amount of reactant left after n-half lives = ?

=Let Initial amount of the reactant = 100 g

n = number of half lives

in this image, you can see solar radiation going through ocean water.

no image, but probably absorption