Question

multiple choice questions

1. what isotope is primarily used in potassium - argon dating?

a) argon - 40
b) potassium - 40
c) uranium - 238
d) lead - 206

1. who discovered radioactivity?

a) albert einstein
b) marie curie
c) isaac newton
d) niels bohr

1. what does uranium decay into in uranium - lead dating?

a) potassium
b) lead
c) argon
d) carbon

1. what is a key limitation of radiometric dating?

a) it can only date organic materials.
b) it requires a closed system.
c) it is only applicable for rocks younger than 1 million years.
d) it cannot be used on lunar samples.

1. what is the half - life of carbon - 14?

a) 5730 years
b) 1.3 billion years
c) 4.5 billion years
d) 100,000 years

Explanation:

1. Potassium - 40 is the radioactive isotope used in potassium - argon dating as it decays to argon - 40 over time.
2. Henri Becquerel discovered radioactivity, but Marie Curie also made significant contributions to the study of radioactivity. Among the given options, Marie Curie is the correct choice.
3. In uranium - lead dating, uranium decays into lead through a series of radioactive decay steps.
4. Radiometric dating requires a closed system, meaning no parent or daughter isotopes have been added or removed over time, which is a key limitation.
5. The half - life of carbon - 14 is 5730 years, which is used to date organic materials.

Answer:

1. B. Potassium - 40
2. B. Marie Curie
3. B. Lead
4. B. It requires a closed system.
5. A. 5730 years