A Rock Sample Contains 1/2 Microgram of the Parent Radioactive

question 89

Multiple Choice

A rock sample contains 1/2 microgram of the parent radioactive isotope U-235 and 1/2 microgram of its daughter isotope Pb-207. If the half-life of this decay is 700 million years, how old is this rock?

• A) 1400 million years
• B) 2100 million years
• C) 700 million years
• D) 350 million years

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Definitions:

Collective Attempts

Joint efforts or actions taken by a group of individuals or entities towards achieving a common goal.

Enduring

Lasting over a long period; demonstrating persistence or continued existence.

Union Formation

The process of organizing and establishing a union, typically involving workers coming together to advocate for their collective rights and interests.

Collective Action

The effort made by a group to reach and implement agreements in the pursuit of a common interest or goal.