Matilda has a 100 g rock sample. She knows that the rock contains uranium-238 and that the half-life of uranium-238 is 4.5 X 109 years. If she cuts the rock sample in half, what happens to the half-life of the uranium?

Half-life is the time required for half of the uranium-238 atoms in a sample to decay. It is a property of uranium-238 and does not depend on how much of it is present, so cutting the rock in half leaves the half-life unchanged at 4.5 × 10⁹ years. The correct choice is “The half-life remains the same.”

AI-written and checked against the verified answer.