Question

match the mother-daughter pair to the time frame they are used to measure.
4 points
1 million to 4.5 billion years up to 60,000 years 100,000 to 4.5 billion years over 100,000 years
c-14 - n-14 □ □ □ □
u-238 - pb-206 □ □ □ □
rb-87 - sr-87 □ □ □ □
k-40 - ar-40 □ □ □ □

Explanation:

• C-14 decays to N-14 with a half-life ~5730 years, so it measures up to ~60,000 years (max for reliable dating).
• U-238 decays to Pb-206 with a half-life ~4.5 billion years, suitable for 1 million to 4.5 billion years.
• Rb-87 decays to Sr-87 with a half-life ~48.8 billion years, used for 100,000 to 4.5 billion+ years.
• K-40 decays to Ar-40 with a half-life ~1.25 billion years, applicable for over 100,000 years.

Answer:

• C-14 - N-14: up to 60,000 years
• U-238 - Pb-206: 1 million to 4.5 Billion years
• Rb-87 - Sr-87: 100,000 to 4.5 Billion years
• K-40 - Ar-40: Over 100,000 years