Aradioactive substance used in nuclear weapons decays at the rate of 3.33.3% per year. calculate the half-life of the radioactive substance.

The amount of substance that is present after t years given that the half-life of the substance is h is calculated through the equation,

   A(t) = A(o)(0.5^t/h)

If after a year, the rate of decay is equal to 33.3% then,

   A(t)/A(o) = (1/3) = 0.5^(1/h)

The value of h from the equation is 0.63 years. 

0.63 years

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0.50 hope this