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3 years ago

If there are 50 grams of U-238 on day zero of radioactive decay, how much will there be after 4.5 billion years

2 answers:

4 0

We use the formula of the half-life to calculate for the remaining U-238 after 4.5 billion years. The formula is expressed as A = A₀ (1/2)^(t/h) where A is the final amount, A₀ is the initial amount of the substance, t is the time and h is the half-life of the substance wherein for U-238 h is equal to 4.47 billion years.

<span>A = A₀ (1/2)^(t/h)
</span>A = 50 (1/2)^(4.5 / 4.47)
A = 24.88 g

kobusy [5.1K]3 years ago

4 0

25 if using usatsyprep

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Use Factor-Label Method:

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3 years ago

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DanielleElmas [232]

Answer:

$\alpha =-2.2669642\times^{-10}rad/s^2$

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Taking our initial (i) point now and our final (f) point one year later, we would have:

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So for our values we have:

$\alpha =\frac{2\pi}{\Delta t}(\frac{1}{T_f}-\frac{1}{T_i})=\frac{2\pi}{31536000s}(\frac{1}{0.0786s+7.03\times10^{-6}s}-\frac{1}{0.0786s})=-2.2669642\times^{-10}rad/s^2$

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3 years ago

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Answer: C

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Explanation:

Given that the half life time = 60.5s

Let No = initial mass = 59g

N = decayed mass

At time t = 0, No = 59g

At time t = 60.5s,

N = No/2 = 59/2

= 29.5g

At time t = 121

N = 29.5/2 = 14.75g

Therefore N = 14.75g

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3 years ago