Question 7 7. Because of the long half-life of $^{238}U$, it is ideal for dating the formation of the Earth and ancient mountain belts. True False
Added by Tyler S.
Close
Step 1
The half-life of a radioactive isotope is the time it takes for half of the isotope to decay. Show more…
Show all steps
Your feedback will help us improve your experience
Emily Anderson and 73 other Physics 101 Mechanics educators are ready to help you.
Ask a new question
Labs
Want to see this concept in action?
Explore this concept interactively to see how it behaves as you change inputs.
Key Concepts
Recommended Videos
Natural uranium is made up of two isotopes: ${ }^{235} \mathrm{U}$ and ${ }^{238} \mathrm{U}$. The halflife of ${ }^{235} \mathrm{U}$ is $7.04 \times 108 \mathrm{y}, 7.04 \times 10^{8} \mathrm{y}$, and the half-life of ${ }^{238} \mathrm{U}$ is $4.47 \times 109 \mathrm{y}$ $4.47 \times 10^{9} \mathrm{y}$. Assuming that all uranium isotopes were created simultaneously and in equal amounts at the same time that Earth was formed, estimate the age of Earth. The current percent abundance of ${ }^{235} \mathrm{U}$ is $0.72 \%$ and for ${ }^{238} \mathrm{U}$ it is $99.28 \% . \underline{\text { Example } 27-7}$
(a) What fraction of the $^{238} \mathrm{U}$ atoms present at the formation of the Earth still exist? Take the age of the Earth to be $4.5 \times 10^{9}$ yr. (b) Answer the same question for $^{235} \mathrm{U}$ Could this explain why there are more than 100 times as many $^{238} \mathrm{U}$ atoms as $^{235} \mathrm{U}$ atoms in the Earth today?
Natural uranium is made up of two isotopes: 235U and 238U. The half-life of 235U is 7.04×10^8 y, and the half-life of 238U is 4.47×10^9 y. 1) Assuming that all uranium isotopes were created simultaneously and in equal amounts at the same time that Earth was formed, estimate the age of Earth. The current percent abundance of 235U is 0.72% and for 238U it is 99.28%. (Express your answer to two significant figures.)
Adi S.
Recommended Textbooks
University Physics with Modern Physics
Physics: Principles with Applications
Fundamentals of Physics
18,000,000+
Students on Numerade
Trusted by students at 8,000+ universities
Watch the video solution with this free unlock.
EMAIL
PASSWORD