The half life of an isotope is 10,000 years. If 12.5% of the parent isotope remains in the rock by the time it is dated, how old is the rock?
a) 10,000 years
b) 20,000 years
c) 30,000 years
d) 40,000 years
e) Not enough information given to answer this question
Ans: c) 30,000 years
You might also like to view...
A country's level of wealth is not the only factor determining the degree of automobile dependency in cities. ________ is also an important factor
A) Availability of transportation alternatives B) Whether a country is developed or developing C) Access to freeways D) Extent of urban decay E) Availability of hybrid vehicles
Which of the following is true of fevers?
A) An increase in body temperature never has beneficial effects. B) A 1°C increase in temperature can be protective. C) A 3°C increase in temperature is invariably fatal. D) None of the above is true.
Which of the following is a correct IUPAC name?
A) 1-isopropyl-1-cyclohexanol B) 1-isopropylcyclohexanol C) trans-1-isopropyl-1-cyclohexanol D) none of these
What does the tendency of micas to produce thin cleavage flakes suggest about its crystal structure?
A) The structure is produced by flow in the igneous rock, aligning glass layers within the crystal structure. B) The structure is characterized by rings that form an interlocking network, forming planar sheets. C) The crystal structure is characterized by complex polymerized mats that form a sheetlike structure. D) The atoms are arranged in orderly arrangements that form strongly bonded sheets separated by weak bonds between the sheets.