If the half-life of an isotope is 3 years, what fraction of the isotope remains after 15 years? (put fraction in as decimal)

The answer is b hope this

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Answerthe energy required is 1.60 × 10⁻¹⁸ j, to three significant figures.explanationwe define electric potential as the ratio electric potential energy to the charge,    then the following gives us the potential difference,      the formula  may be on your formula sheet.the change in electric potential energy would be the energy that would needed to move it from point a to point b. solving for that, we get    using q = 8.00  × 10⁻¹⁹ c and  δv = 2.00 v, we get    the energy required is 1.60 × 10⁻¹⁸ j, to three significant figures.

The geological theory that states that pieces of earth's lithosphere are in constant slow motion is the theory of plate tectonics.