Question

Which of the following element transformations is NOT used as the basis of a radioactive rock-dating method?

Options

• Uranium changing into lead

• Rubidium-87 changing into strontium

• Rubidium-87 changing into lead

• Potassium-40 changing into argon

Answer 1

The recognized transformations are uranium into lead, potassium-40 into argon, and rubidium-87 into strontium. Rubidium-87 changes into strontium, not lead, so the first option describes a transformation that is not used.