Answer is: <span>the size of the sample of uranium-238 does not affect its half-life. </span><span> The half-life for the
radioactive decay of U-238 is 4.5 billion years and is independent of initial
concentration (size of the sample). </span>Half-life <span>is
the time required for a quantity (in this example number
of radioactive uranium) to reduce to half its initial
value.</span><span>
