Question 1

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Accepted Answer

(B) Determining the age of rocks and fossils
Explanation: Radiometric dating is a method used to determine the age of rocks and fossils by measuring the decay of radioactive isotopes within them.

Question 2

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Accepted Answer

(C) Carbon-14
Explanation: Carbon-14 is commonly used in radiometric dating to date organic materials, such as bones and wood, up to about 50,000 years old.

Question 3

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Accepted Answer

(A) 5730 years
Explanation: The half-life of Carbon-14 is 5730 years, meaning it takes this amount of time for half of the Carbon-14 in a sample to decay.

Question 4

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Accepted Answer

(B) Uranium-lead dating
Explanation: Uranium-lead dating is used to date rocks that are billions of years old due to the long half-lives of uranium isotopes.

Question 5

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Accepted Answer

(C) The predictable decay of radioactive isotopes
Explanation: Radioisotope dating, or radiometric dating is based on the predictable decay of radioactive isotopes, which allows scientists to determine the age of a sample by measuring the remaining amount of the isotope and its decay products.

Question 6

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Accepted Answer

(D) Potassium-40
Explanation: Potassium-40 is the isotope used in Potassium-Argon dating, where it decays to Argon-40, which is used to date volcanic rocks and minerals.

Question 7

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Accepted Answer

(C) Insufficient remaining Carbon-14
Explanation: It is difficult to use radiocarbon dating on samples older than 50,000 years because the remaining amount of Carbon-14 is too small to accurately measure.

Question 8

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Accepted Answer

(B) Thermoluminescence dating
Explanation: Thermoluminescence dating is a non-radiometric method that measures the accumulated radiation dose in minerals and is used to date ceramics, sediments, and rocks.

Question 9

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Accepted Answer

(B) It is the temperature below which isotopes are locked in a mineral
Explanation: The closure temperature is the temperature below which a mineral becomes a closed system for isotopes, meaning that no isotopes can enter or leave the mineral, allowing accurate radiometric dating.

Question 10

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Accepted Answer

(B) Potassium-argon dating
Explanation: Potassium-argon dating is commonly used to date recent lava flows because it can date volcanic rocks and ash deposits over a wide range of geological time scales.

Question 11

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Accepted Answer

(C) To determine the absolute age of rocks
Explanation: Radiometric dating of rocks is primarily used to determine their absolute age by measuring the decay of radioactive isotopes within the minerals.

Question 12

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Accepted Answer

(B) Potassium-argon dating
Explanation: Potassium-argon dating is commonly used to date ancient igneous rocks, as it measures the decay of potassium-40 to argon-40.

Question 13

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Accepted Answer

(B) Uranium-238
Explanation: In the Uranium-Lead dating method, Uranium-238 is the parent isotope that decays to lead-206, which is used to date rocks that are millions to billions of years old.

Question 14

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Accepted Answer

(C) Zircon
Explanation: Zircon is commonly used in Uranium-Lead dating because it can incorporate uranium atoms into its crystal structure but excludes lead, making it an ideal candidate for this dating method.

Question 15

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Accepted Answer

(A) Longer half-lives are better for dating older rocks
Explanation: Isotopes with longer half-lives are better for dating older rocks because they remain measurable over longer time spans, allowing for the determination of the ages of ancient rocks.

Question 16

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Accepted Answer

(A) The decay of Rubidium-87 to Strontium-87
Explanation: The Rubidium-Strontium dating method is based on the radioactive decay of Rubidium-87 to Strontium-87, which is used to date rocks and minerals.

Question 17

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Accepted Answer

(A) To ensure no loss or gain of parent or daughter isotopes
Explanation: A closed system is essential in radiometric dating to ensure that the rock sample has not lost or gained parent or daughter isotopes, which would otherwise affect the accuracy of the dating.

Question 18

Answer

Accepted Answer

(C) 4.5 billion years
Explanation: The half-life of uranium-238 is approximately 4.5 billion years, making it suitable for dating the oldest rocks on Earth.

Question 19

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Accepted Answer

(B) Potassium-argon dating
Explanation: Potassium-argon dating is suitable for dating volcanic ash layers because it measures the decay of Potassium-40 to Argon-40, which is trapped in the volcanic minerals.

Question 20

Answer

Accepted Answer

(B) A graph that plots the ratio of parent to daughter isotopes to determine the age of a sample
Explanation: An isochron is a graph used in radiometric dating to plot the ratio of parent to daughter isotopes, helping to determine the age of a rock sample by eliminating the need for knowledge of the initial amount of daughter isotope.

Question 21

Answer

Accepted Answer

(A) The time it takes for half of the parent isotope to decay into the daughter isotope
Explanation: In radiometric dating, the half-life is the time required for half of the parent isotope in a sample to decay into its daughter isotope, which is a key concept in determining the age of rocks.

Question 22

Answer

Accepted Answer

(B) Uranium-235
Explanation: Uranium-235 is commonly used in dating ancient geological events, such as the formation of the Earth, because of its long half-life and presence in many rocks and minerals.

Question 23

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Accepted Answer

(C) Igneous rocks
Explanation: The potassium-argon method is typically used to date igneous rocks because these rocks contain minerals that trap potassium-40, which decays to argon-40 over time.

Question 24

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Accepted Answer

(C) To calculate the accurate age of the rock
Explanation: Knowing the initial amount of the daughter isotope is important in radiometric dating to accurately calculate the age of the rock, as it allows for the correction of any pre-existing daughter isotopes.

Question 25

Answer

Accepted Answer

(B) Uranium-Lead dating
Explanation: Uranium-Lead dating is used to date the age of the Earth due to its ability to date very old rocks and minerals, providing estimates of Earth's formation at about 4.5 billion years ago.

Question 26

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Accepted Answer

(B) It provides precise and absolute ages for geological events
Explanation: Radiometric dating is significant because it provides precise and absolute ages for geological events, helping to construct accurate geological time scale.

Question 27

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Accepted Answer

(D) Samarium-Neodymium dating
Explanation: The Samarium-Neodymium dating method uses the decay of Samarium-147 to Neodymium-143, which is useful for dating ancient rocks and meteorites.

Question 28

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Accepted Answer

(B) To provide cross-validation and increase accuracy
Explanation: Using multiple radiometric dating methods on the same rock sample provides cross-validation and increases the accuracy and reliability of the age determination.

Question 29

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Accepted Answer

(C) Argon-argon dating
Explanation: Argon-argon dating is best suited for dating very young geological materials, such as recent volcanic eruptions, due to its high precision and ability to date events from a few thousand to several billion years ago.

Question 30

Answer

Accepted Answer

(B) It records the damage trails (tracks) left by fission fragments in minerals
Explanation: Fission track dating is useful for dating certain types of minerals in rocks because it records the damage trails (tracks) left by fission fragments, which can be counted to determine the age of the sample.

Category: Geochronology

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