Question

Alpha decay

Beta decay

Electron capture

Gamma emission

Answer 1

What is the question?

Answer 2

alpha

Answer 3

Samarium has a half-life of approximately 106 billion years. If you found a sample of samarium from the beginning of Earth's history, approximately 4.6 billion years ago, which would be the best approximation of the amount of parent isotope left in the rock?

Nearly 100 percent

50 percent

25 percent

Less than 10 percent

Answer 4

i dont know it varies as time power of e
so the decay goes exponentially. . .
i guess its still 10%

Answer 5

The following graph shows the rates of decay for four parent isotopes. Based on the graph, which parent isotope most likely has a half-life of 13 billion years?



Public Domain

A

B

C

D

Answer 6

where is graph???

Answer 7

ill just skip that one because i cant ggrauph on here

Answer 8

i just put te graph on here

Answer 9

i guess its c
because have to take estimate as half point of curve would lie near 13bn so it must be c

Answer 10

Uranium-238 has a half-life of 4.5 billion years. Given that scientists estimate Earth's age to be 4.6 billion years, what is the most likely percentage of parent to daughter isotopes of this element currently existing on Earth?

10 percent

25 percent

50 percent

75 percent

Answer 11

50% i guess after half life the decay becomes slow w.r.t. to the time.

Answer 12

The following table shows the currently accepted half-life values for four parent isotopes.

Parent Isotope Currently Accepted Half-Life Values
Uranium-238 4.5 billion years
Uranium-235 704 million years
Thorium-232 14.0 billion years
Rubidium-87 48.8 billion years
Potassium-40 1.25 billion years
Samarium-147 106 billion years

Earth is approximately 4.5 billion years old. Given this information and the data in the table, which of the following isotopes could today contain less than 50 percent of its parent isotope?

Rubidium-87

Thorium-232

Uranium-235

Uranium-238

Answer 13

uranium 238 is the answer. . .

Answer 14

A substance has a half-life of 100,000 years and an initial mass of 1,000 grams. How many years will pass before only 250 grams of the substance's parent material is left?

10,000

50,000

200,000

300,000

Answer 15

c 200000 is the answer or i may say double as its half life. so that only 25% of it remains

Answer 16

Carbon-14 has a half-life of approximately 5,730 years. How many half-lives have occurred in a sample that contains less than 10 percent of the original amount of the parent isotope?

1

2

3

4

Answer 17

you may say half+half of half+half of half of half+4th time so that it may be less than 10%
or at third step deay would be 87.5% so we need forth step so that it may remain less than 10

Answer 18

Public Domain

Potassium-40 has a half-life of approximately 1.25 billion years. Approximately how many years will pass before a sample of potassium-40 contains one-sixteenth the original amount of parent isotope?

1.25 billion

2.5 billion

3.75 billion

5 billion



last one n thanks for all your help sorry to keep you u

Answer 19

4 times as1.25 that is 5 billion that is again 1/\[2^{2}\]

Answer 20

so which i s the answer

Answer 21

d 5bn

Answer 22

thank enjoy your sleep