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Anettt [7]
2 years ago
13

A radioactive nucleus has a half-life of 5*108 years. Assuming that a sample of rock (say, in an asteroid) solidified right afte

r the solar system formed, approximately what fraction of the radioactive element should be left in the rock today? The age of the solar system is 4.5*109 years. (No calculator is necessary, but if it helps use it.)
Physics
1 answer:
Gre4nikov [31]2 years ago
7 0

Answer:

0.002

Explanation:

The half-life of the radioactive nucleus is related to its quantity, by the following equation:

N_{t} = N_{0}2^{-t/t_{1/2}}

<u>Where:</u>

<em>N(t): is the quantity of the radioactive nucleus at time t</em>

<em>N₀: is the  initial quantity of the radioactive nucleus</em>

<em>t: is the time = 4.5x10⁹ years</em>

<em>t(1/2): is the half-life of the radioactive nucleus = 5x10⁸ years</em>

\frac{N_{t}}{N_{0}} = 2^{-4.5 \cdot 10^{9} y/5 \cdot 10^{8} y} = 2 \cdot 10^{-3}

Therefore, the fraction of the radioactive element in the rock today is 0.002.

I hope it helps you!  

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Answer:

the only effect it has is to create more induced charge at the closest points, but the net face remains zero, so it has no effect on the flow.

Explanation:

We can answer this exercise using Gauss's law

      Ф = ∫ e . dA = q_{int} / ε₀

field flow is directly proportionate to the charge found inside it, therefore if we place a Gaussian surface outside the plastic spherical shell.  the flow must be zero since the charge of the sphere is equal  induced in the shell, for which the net charge is zero. we see with this analysis that this shell meets the requirement to block the elective field

From the same Gaussian law it follows that if the sphere is not in the center, the only effect it has is to create more induced charge at the closest points, but the net face remains zero, so it has no effect on the flow , so no matter where the sphere is, the total induced charge is always equal to the charge on the sphere.

5 0
2 years ago
Complete the passage to summarize factors affecting the speed of a wave. The material or substance that a wave moves through is
pantera1 [17]

the first one is medium, the second one is type, and the third one is temperature . if i gave the correct answer, please give best answer x

6 0
2 years ago
Read 2 more answers
A uniform cylindrical steel wire (density: 7.8 x 103 kg/m3), 58.0 cm long and 1.34 mm in diameter, is fixed at both ends. To wha
lbvjy [14]

Answer:

T= 354.65 N

Explanation:

Given that

ρ= 7800 kg/m³

L= 58 cm

d=1.34 mm

f= 311 Hz

T= Tension

Speed of wave ,V

V = f λ      

V = f L

V= 311 x 0.58 m/s

V=180.38 m/s

Area of cross sectional

A= πr² mm²

A= 3.14 x 0.67² mm²

A=1.41 mm²

Mass = Density x Volume

m=7800\times 1.41\times 10^{-6}\ kg/m

m=0.0109 kg/m

Tension ,T

T=m V^2

T= 0.0109 x 180.38² N

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3 0
2 years ago
A hot piece of iron is thrown into the ocean and its temperature eventually stabilizes. Which of the following statements concer
777dan777 [17]

Answer:

E. The ocean gains more entropy than the iron loses.

Explanation:

When there is a spontaneous process , entropy of the system increases . Here hot iron is losing entropy and ocean is gaining entropy . Net effect will be gain of entropy . That means entropy gained by ocean is more than entropy lost by iron .

Hence option E is correct .

8 0
2 years ago
An owl has a mass of 4.00 kg. It dives to catch a mouse, losing 800.00 J of its GPE. What was the starting height of the owl, in
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Answer:

height =20m

Explanation:

gpe=mgh

800=4×10×x

40x=800

x=20

3 0
2 years ago
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