# Which of the following statements about radioactive dating is true? a. Radioactive decay is the rate at which new atoms form. b. During radioactive decay, atoms break down, releasing particles or energy. c. The rate of decay of a radioactive

35,675 results
1. ## Algebra 2 help...

A half life of a certain radioactive is 36 days. An initial amount of the material has a mass of 487 kg. Write an exponential function that models the decay of this material. Find how much radioactive material remains after 5 days. Round your answer to the

Which of the following statements about radioactive dating is true? a. Radioactive decay is the rate at which new atoms form. b. During radioactive decay, atoms break down, releasing particles or energy. c. The rate of decay of a radioactive element cannot

3. ## Math

The half-life of a certain radioactive material is 38 days. An initial amount of the material has a mass of 497 kg. Write an exponential function that models the decay of this material. Find how much radioactive material remains after 4 days. Round your

4. ## chem

Complete the following radioactive decay problem. 234 4 U ---> He+ 92 2 how do i do this?

5. ## Science-3 questions.

Which of the following best describes the climates of Europe and North America during the 1.8 million years of the Quaternary period? hot and dry cool and rainy periods followed by droughts warm and mild a series of ice ages followed by periods when the

6. ## Differential Equations

Model radioactive decay using the notation t = time (independent variable) r(t) = amount of particular radioactive isotope present at time t (dependent variable) -λ = decay rate (parameter) Note that the minus sign is used so that λ > 0 a) Using this

7. ## Science

What can scientists learn from the rate at which radioactive elements decay? A. a rock's absolute age* B. the relative age of rock layers C. where one soil horizon ends and the next begins D. the difference between molds and casts. The relative age of a

8. ## calculus

Carbon-14 is a radioactive substance produced in the Earth's atmosphere and then absorbed by plants and animals on the surface of the earth. It has a half-life (the time it takes for half the amount of a sample to decay) of approximately 5730 years. Using

9. ## Science

Which of the following units are in order from smallest to largest? a) Epoch, period, era. b) Era, epoch, period. c) Period, era, epoch. d) Epoch, era, period. True or False? Folding, as well as motion along faults, can change the position of rock layers

10. ## science

Examine the following equations. A. 23490Th→23491Pa+0−1e+γ B. 60∗27Co→6027Co+γ C. 23490Th→23088Ra+42He D. 146C→147N+0−1e Which equation or equations represent gamma decay? B C A and B A A and D D C and D Which describes the relationship of

11. ## Calculus-Modeling Equations

An unknown radioactive element decays into non-radioactive substances. In 420 days the radioactivity of a sample decreases by 39 percent. 1.What is the half-life of the element? 2.How long will it take for a sample of 100 mg to decay to 46 mg?

12. ## 8th Grade Earth Science Help?

Which of the following terms refers to the time it takes for one-half of the radioactive atoms in a sample of a radioactive element to decay? - relative age - absolute age - potassium-argon data - half-life** Is my answer correct?

13. ## science

during radioactive decay atoms of a radioactive element break down and change into other atoms of another element-all at once a) true b) false

15. ## Math

A radioactive substance decays according to the formula Q(t) = Q0e−kt where Q(t) denotes the amount of the substance present at time t (measured in years), Q0 denotes the amount of the substance present initially, and k (a positive constant) is the decay

17. ## Math - D.E.Q.

The half-life of a radioactive isotope is the amount of time it takes for a quantity of radioactive material to decay to one-half of its original amount. i) The half-life of Carbon 14 (C-14) is 5230 years. Determine the decay-rate parameter  for C − 14.

18. ## Chemistry (Check)

Classify each of these statements as always true, sometimes true, or never true. __ST___13.In an equation, a substance is shown to be in the gaseous state by placing an upward-pointing arrow after its formula. ___ST___14. Atoms are destroyed in a chemical

19. ## Calculus

[Exponential growth & decay] The half-life of radioactive strontium-90 is approximately 29 years. In 1965, radioactive strontium-90 was released into the atmosphere during testing of nuclear weapons, and was absorbed into people's bones. How many years

20. ## chemistry

a certain radioactive nuclide has a half life of 5.00 hour. Calcuate the decay rate for 1.000 mole of this nuclide __________ decay s-1

21. ## Science

How are modern items made to look like ancient artifacts? (This is about radioactive decay and dating.)

22. ## Science

How does radioactivity make it possible to understand how Earth can be so old and still have a hot interior? (1 point) A.Radioactive elements trap heat from underground magma chambers. B.Radioactive elements absorb heat from the atmosphere and release it

23. ## Math

A radioactive substance decays according to the formula Q(t) = Q0e−kt where Q(t) denotes the amount of the substance present at time t (measured in years), Q0 denotes the amount of the substance present initially, and k (a positive constant) is the decay

24. ## science

why is it rare for the soft parts of an organism to become a fossil? a) the soft parts take a long time to decay b) the soft parts can be eaten by animals***** c) the soft parts cannot be buried in sediment d) the soft parts form petrified fossils which of

25. ## Science

What process involves the comparison of rock layers with others in a sequence to determine its age? radioactive decay radiometric dating relative dating absolute dating To determine the most accurate and precise age of Earth's oldest rocks, geologists

26. ## MATH!

The mass of a radioactive substance follows an exponential decay model, with a decay rate of 5% per day. A sample of this radioactive substance was taken six days ago. If the sample has a mass of 3 kg today, find the initial mass of the sample. Round your

27. ## Science- Earth and its History

What can scientists learn from the rate at which radioactive elements decay? A. a rock's absolute age* B. the relative age of rock layers C. where one soil horizon ends and the next begins D. the difference between molds and casts. After six half-lives,

28. ## Science

What can scientists learn from the rate at which radioactive elements decay? A. a rock's absolute age* B. the relative age of rock layers C. where one soil horizon ends and the next begins D. the difference between molds and casts. After six half-lives,

29. ## 1 Physics Question

Can someone tell me how to solve this? I’m having trouble with equations: “A sample contains 20 kg of radioactive material. The decay constant of the material is 0.179 per second. If the amount of time that has passed is 300 seconds, how much of the

30. ## Science

3. What can scientists learn from the rate at which radioactive elements decay? (1 point)

31. ## Chemistry

Radioactive decay is first order in the decaying isotope. For example, strontium-90 contained in fallout from nuclear explosions decays to yttrium-90 and a beta particle. Write the rate law for the decay of strontium-90. Can you please take me step by stem

32. ## biology

how do scientists use radioactive dating to approximate a rock's age

33. ## calculus

The rate at which an amount of a radioactive substance decays is modeled by the differential equation dA/dt = kA, where A is the mass in grams, t is the time in years, and k is a constant. Answer the following. a) If a 100-gram sample of the radioactive

34. ## chemistry

Some radioactive nuclides have very short half-lives, for example, I-31 has a half-life of approximately 8 days. Pu-234, by comparison has a half-life of 24,000 years. Explain why both of these examples are dangerous, even though their half-lives are very

35. ## SCIENCE

We did a radioactive decay and half life lab with m&ms and I do not understand these conclusion questions: 1. how many half lives would it take for 500 nuclei to decay to 6.25% of the original number of nuclei? My ans: 3125?- do not think that's right! 2.

36. ## science - biology

A photosynthesis experiment uses Chlorella to track the route taken by 14C in photosynthesis. The 14C is provided from CO2 and no new sources of CO2 are available. After the experiment the scientist extracts all of the starch produced and analyses the

37. ## math

Carbon 14 (14C) dating assumes that the carbon dioxide on Earth today has the same radioactive content as it did centuries ago. If this is true, the amount of 14C absorbed by a tree that grew several centuries ago should be the same as the amount of 14C

38. ## Science

A human body required 0.01 m activity of radioactive substance after 24 hours .Half li of radioactive substance is 6 hours .Then injection of maximum activity of radioactive substance that can be injected is : a). 0.08 b). 0.04 c). 0.16 d). 0.32

39. ## Science

It can be inferred from the passage that radioactive dating is important for estimating the age of A) all known meters B) all existing planets C) the earth D) the trees

40. ## Science

1. Radioactive parent elements will become stable daughter elements through the process of (1 point) absolute dating. radioactive decay. radiometric dating. stabilization

41. ## Calculus

The rate of decay is proportional to the mass for radioactive material. For a certain radioactive isotope, this rate of decay is given by the differential equation dm/dt = -.022m, where m is the mass of the isotope in mg and t is the time in years. A. If

42. ## science

Which statement best explains why dating geologic materials from the Quarternary Period uses a different radioactive isotope than for materials from the cambrian Period? a. all rocks contain radioactive substances. b. some isotopes decay faster than

43. ## chem

Potassium-40 undergoes three different modes of radioactive decay (Beta decay, Positron decay, and Electron Capture decay). Write balanced nuclear reactions for each of these decay modes. Are the products stable (not radioactive)?

44. ## Physics

Estimate the De Broglie wavelength of: a) The Moon orbiting the Earth; b) A nitrogen molecule at room temperature; c) A well-served tennis ball; d) An alpha particle emitted in the radioactive decay of 210Po; e) A beta particle emitted in the radioactive

45. ## chem

a) Potassium-40 undergoes three different modes of radioactive decay (Beta decay, Positron decay, and Electron Capture decay). Write balanced nuclear reactions for each of these decay modes. Are the products stable (not radioactive)? b) Potassium-40 has a

46. ## Geology

Does this sound right? Describe your assigned method and how it is used to evaluate geologic time. My assigned method was Absolute Dating / Numerical Age. Absolute Dating / Numerical Age is the process that assigns a numerical age ( this tells how old a

47. ## Physics ...

Hi Radioactive decay - A radioactive nuclide has a decay constant of - 10^-6 s-1 what is its half life ? I have come up with is IN (2) / 0.000001 s-1 = 693147.18055 which i am having troube working into real figures Can anyone help please .. thanks

48. ## Physics

Hi Radioactive decay - A radioactive nuclide has a decay constant of - 10^-6 s-1 what is its half life ? I have come up with is IN (2) / 0.000001 s-1 = 693147.18055 which i am having troube working into real figures Can anyone help please .. thanks

49. ## Chemistry

How many half lives will it take for a sample of a radioactive isotope containing 20000 radioactive nuclei to decay to 2000 radioactive nuclei

50. ## Science

What can scientists learn from the rate at which radioactive elements decay? A. a rock's absolute age* B. the relative age of rock layers C. where one soil horizon ends and the next begins D. the difference between molds and casts. After six half-lives,

51. ## Science

What can scientists learn from the rate at which radioactive elements decay? A. a rock's absolute age* B. the relative age of rock layers C. where one soil horizon ends and the next begins D. the difference between molds and casts. After six half-lives,

52. ## Science

Choose the explanation that does the following: (1) identifies the element used in carbon dating and (2) explains why the element is used. A. iodine-131; iodine is present in the thyroid glands, is radioactive, and has a very long half-life B. nitrogen-14;

53. ## science

A 10g sample of radioactive substances is lift to decay for five half-lives. How much of the radioactive substance remains?

54. ## Science

How does radioactivity make it possible to understand how Earth can be so old and still have a hot interior? A: radioactive elements trap heat from underground magma chambers. B: radioactive elements absorb heat from the atmosphere and release it

Radioactive decay is the process by which an unstable element transforms into different element, typically releasing energy as it does so. For 500g of a radioactive substance with a half-life of 5.2 hours, the amount remaining is given by the formula

56. ## physics

a radioactive sample has a decay rate R of 518 decay/min at time t=7 min and 156 decay/ min at time t=17 min. calculate the decay constant and the initial decay rate?

57. ## geology / science

the age of granite can be determind using radiometric dating, explain the basis for the determination of a 238 U- Pb radiometric date of 1120 Ma for a granite. I have as the answer 238 U decays to Pb with an experimental law, that is the amount of U and Pb

58. ## CHEMISTRY HELP !!!!

Which of the following statements is/are CORRECT? 1. Naturally occurring isotopes account for only a small fraction of known radioactive isotopes. 2. A few radioactive isotopes with long half-lives, such as U-235 and U-238, are found in nature. 3. Trace

59. ## Earth Science

1. Is it true that since energy cannot be created nor destroyed, the total energy of the river system remains constant? 2. What is the source of energy that powers the water cycle? a. sunlight insolation b. kinetic energy c. radioactive decay d.

60. ## Science

What can scientists learn from the rate at which radioactive elements decay?

61. ## earth

3. What can scientists learn from the rate at which radioactive elements decay?

62. ## Science

3. What can scientists learn from the rate at which radioactive elements decay? (1 point)

63. ## algebra

Scientists can determine the age of ancient objects by a method called radio carbon dating. The bombardment of the upper atmosphere by cosmic rays converts nitrogen to a radioactive isotope 14C of carbon with a half-life of about 5710 years. Vegetation

64. ## math

the amount of radioactive substance prsent at anytime is given by q(t)=Q0e-0.1 How will it take for the radioactive substance x to decay to 30% of its original amount?

65. ## science

Hello! I need help with some Science things. 1. Where is a good place to find a picture that describes radioactive decay, fussion and fission/ 4. Scientists use the amount of radioactive isotopes found in rocks and fossils to calculate their ages. This

66. ## chemistry

A particular radioactive substance has a half-life of 4 minutes. How long will it take for 250 g of this radioactive material to decay to less than 0.1g? 24 min 36 min 40 min 48 min 72 min I got 32 min but that not one of the choices. Please help

67. ## chemistry

The radioactive decay of carbon-14 is first-order and the half-life is 5800 years. While a plant or animal is living, it has a constant proportion of carbon-14 (relative to carbon-12) in its composition. When the organism dies, the proportion of carbon-14

68. ## phys

Although most natural potassium nuclei are stable 39K (93.3%) or 41K (6.7%) nuclei, about 0.0117% are radioactive 40K nuclei, which have a half-life of 1.26 billion years. What fraction of all the potassium nuclei in your body will undergo radioactive

69. ## Physic

A radioactive element x has half life of 30 days and will decay to become another new element Y.. a) calculate decay constant b) how long it will take for 90% of the no.Of atom in radioisotope x to decay?

70. ## Physic

A radioactive element x has half life of 30 days and will decay to become another new element Y.. a) calculate decay constant b) how long it will take for 90% of the no.Of atom in radioisotope x to decay?

71. ## Physic

A radioactive element x has half life of 30 days and will decay to become another new element Y.. a) calculate decay constant b) how long it will take for 90% of the no.Of atom in radioisotope x to decay?

72. ## chemistry

Situation: You have 100ml of isotopically labelled water 3H2o. That is, the water is made with the radioactive isotope of hydrogen, tritium, 3H. Compounds that contain radioactive isotopes are called "hot." You pour this 100 mL of "hot" water into the

73. ## Science

Radioactive substance decays so that after t years, the amount remaining, expressed as a percent of the original amount, is A(t)=100(1.6)^(-t). a) Determine the function A’, which represent the rate of decay of the substance. b) what is the half-life for

74. ## chemistry

these two radioactive elements decay by electron capture (EC). Write the nuclear reactions for each decay including the formation of the daughter products: a. 35 S + 0 e → 16 -1 b. 69 Sr + 0 e → 35 -1

75. ## College Algebra

Plutonium-238 is used in bombs and power plants but is dangerously radioactive. It decays very slowly into radioactive materials. If you started with 300 grams today, a year from now you would still have 297.6 grams. Construct an exponential function to

76. ## Algebra

A defective nuclear reactor is leaking radioactive iodine-131. The rate of decay of iodine-131is given by the function defined by A(t)=A_0 e^(-0.087t), where t is time in days. How long will it take any quantity of iodine-131 to decay to 25% of its initial

77. ## earth science

what radioactive isotope would be most useful in dating a mastodont bone ?why?

78. ## chemistry

The question I am having trouble with is: Scientists originally were uncertain whether the oxygen gas produced during photosynthesis came from CO2, H2O, or from both. How could radioisotope tracers be used to settle that question? Chemistry - DrBob222 6CO2

79. ## math

Show that if a radioactive substance has a half life of T, then the corresponding constant k in the exponential decay function is given by k=-ln(2)/T I'm confused about how to show that that is true.

80. ## chemistry

Radioactive waste is difficult to dispose of due to the long time periods needed before the radiation effectively disappears. The US protocol is to store the waste for 10 half-lives of the material after which the waste is no longer considered radioactive.

81. ## math

An unknown radioactive element decays into non-radioactive substances. In 100 days the radioactivity of a sample decreases by 64 percent. a)(a) What is the half-life of the element? half-life: b)How long will it take for a sample of 100 mg to decay to 51

82. ## Physical Science

What is an example of radioactive decay?

83. ## biology

14 points Save A photosynthesis experiment uses Chlorella to track the route taken by 14C in photosynthesis. The 14C is provided from CO2 and no new sources of CO2 are available. After the experiment the scientist extracts all of the starch produced and

84. ## math

The exponential function N = 500 × 0.74t, where t is measured in years, shows the amount, in grams, of a certain radioactive substance present. What is the monthly percentage decay rate? (Round your answer to one decimal place.) % (d) What is the

85. ## physics

if 5/6th of a radioactive sample decay in 70 years and 1/6th remain. how can you find the half life without knowing the decay constant can you help?

86. ## math

if the rate for radioactive decay for a substance is r=-.0063 and time is being measured in days how do you find the half-life of the substance to the nearest hour?

87. ## Science

Which type of dating do index fossils provide the most help for? A. carbon-14 B. radioactive C. relative D. absolute

88. ## science

when radioactive decay occurs what happens

89. ## math

39mg radioactive with 1/2 life is decay total in 2.5 years. How many mg it remain if half of the amount is decay in 2 years? Thank you!

90. ## science

I'm doing Science right now. I have the answers down for most of them but I'm not sure if I am right..... Can u pls help me and tell me if my answers r right? I suck at science :S 1.A 2.C 3.B 4.D 5.D 6.A 7.? 8.A 9.E 10.C 11.A 12.D 13.C 14.B 15.? 16.? 17.?

91. ## Science

When Marie Curie Isolated uranium from pitchable, she realized that the [itchable was more radioactive than the uranium she had extracted. What did she conclude about her observations? pitchblende itself is a radioactive element the pitchblende sample

92. ## Biology

How a radioactive element will decay over time?

94. ## Engineering Math

An unknown radioactive element decays into non-radioactive substances. In 120 days the radioactivity of a sample decreases by 59 percent. What is the half life of the element? How long will it take for a sample of 100 mg to decay to 77 mg? The answer is

95. ## Science

If a radioactive isotope has half life of 5 days,how long will it take for its radioactive strength to be a maximum of one thousandth,(1/1000) of its original value?

96. ## Chemistry

compare and contrast the three types of radioactive decay

97. ## Biology

Explain how the half-life of a radioactive isotope affects the usefulness of that isotpe in dating specific types of rock?