Answer:
Hello your question is poorly written below is the well written question
Uranium, an important component of both nuclear weapons and nuclear reactors, has two major isotopes, U-238, which has a half-life of approximately 4.5 billion years, and U-235, which has a half-life of approximately 700 million years. Both were present in equal amounts at the time of the creation of the Earth, 4.5 billion years ago. How many years after the creation of the Earth had the amount of radiation from uranium decayed to half the amount present at the time of the creation of the Earth
Answer : 140 billion years
Explanation:
Given that :
U-238 h1/2 = 4.5 billion years
U-235 h1/2 = 700 million years
At the beginning both Isotopes where present in equal amount
Determine the T years before the amount of Uranium decays to Half
T = ? N'2 = N1 / 2
we know that N = No ( 1/2 )^h where h = time / half-life time
attached below is the detailed solution of the given problem
The equation for carbon-14 emission by Radium-223 nuclei is given below:

<h3>What is radioactivity?</h3>
Radioactivity is the spontaneous decay of a substance with emission of radiation.
The equation for carbon-14 emission by Radium-223 nuclei is given below:

In conclusion, the emission of carbon-14 by Radium-223 nuclei produces Lead-209 nuclei.
Learn more about radioactivity at: brainly.com/question/3603596
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Answer:
Crystalization is solidfying of atoms or molecules or things,,it can be speeded up depends on nature of something in terms of it's molecular force of attraction eg sand and loam soil also temperature and pressure above the sure to be crystalized
An igneus rock is formed where magma(molten rock) cool and solify(crystalized especially in volcanoes areas
I believe the answer is B. a million or more.
The mass decay rate is of the form

where
m₀ = 3000 g,the initial mass
k = the decay constant
t = time, years.
Because the half-life is 30 years, therefore

After 60 years, the mass remaining is

Answer: 750 g