If a radioactive element has a half-life of 5760 years, and the ...

[gbarreiro]

If a radioactive element has a half-life of 5760 years, and the amount of parent material remaining is one-fourth of the original amount, the specimen is about
 
  A) 11,520 years old.
  B) 17,280 years old.
  C) 23,040 years old.
  D) 28,800 years old.

Question 2

What are the limitations in obtaining radiometric dates?
 
  What will be an ideal response?

[Jmfn03]

Answer to Question 1

Answer: A

Answer to Question 2

Answer: When using the half-life method, scientists assume a closed system where there has been no addition or loss of parent or daughter products. If this assumption is not true, age determination will be wrongthe age will be either too old or too young. Another limitation exists for rocks subjected to metamorphism in which the rock's age has been reset. Making sure that a good sample is used, and careful cross checking between samples increases accuracy.

[gbarreiro]

TYSM

[debra928]

Gracias!