A radioactive 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.

Answer: 0.63 years