Purchase Solution

Not what you're looking for?

A threory of nuclear astrophysics is that all the heavy elements like uranium are formed in supernova explosions of massive stars, which immediately release the elements into space. If we assume that at the time of the explosion there were equal amounts of 235U and 238U, how long ago were the elements that formed our Earth released, given that the present 235U/238U ratio is 0.007? (The half-lives of 235U and 238U are 0.70 x 10^9 yr and 4.47 x 10^9 yr, respectively)

##### Solution Preview

If N0 is the initial quantity, after a time t years, the amount of quantity of radioactive material left N = N0*exp(-lambda*t), where lambda = 0.693/half life.
<br><br>Given that N0 was same initially for ...

##### Classical Mechanics

This quiz is designed to test and improve your knowledge on Classical Mechanics.

##### Variables in Science Experiments

How well do you understand variables? Test your knowledge of independent (manipulated), dependent (responding), and controlled variables with this 10 question quiz.

##### The Moon

Test your knowledge of moon phases and movement.

##### Intro to the Physics Waves

Some short-answer questions involving the basic vocabulary of string, sound, and water waves.