Concept explainers
Strontium-90 (90Sr) is a by-product of nuclear fission with a half-life of approximately 28.9 yr. After the Chernobyl nuclear reactor accident in 1986, large areas surrounding the site were contaminated with 90Sr. If 10
Evaluate the function for the given values oft and interpret the meaning in context. Round to 3 decimal places if necessary. (See Example 5 )
a. A(28.9)
b. A(57.8)
c. A(100)
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- Radioactive cesium-137 has a half-life of 30.17 years. How much of an initial amount of 1,000 kilograms of cesium-137 will remain after 100 years?arrow_forwardInitially, 10 grams of a radioactive substance were found in a sample. It was observed that 20% of the initial amount of radioactive substance disintegrated after 2 hours (that is, 8 grams remain after 2 hours). Find the half-life of the radioactive substance (that is, the time it takes for one- half of the initial amount to disintegrate) if the rate of disintegration of the radioactive substance is In z 1 2 0.7 proportional to the amount of the substance present at time t. You must begin your solution process by 3 considering the proportional relationship presented below. Use the natural logarithm table to the right 1.1 to provide an approximate answer. Your work must support your answer. 4 1.4 1.6 dA a A 6 1.8 dt 1.9 2.1 9 2.2 10 2.3 7,arrow_forwardradon is a colorless, odorless gas that is naturally released by rocks and soils and may concentrate in tightly closed houses. because radon is slightly radioactive, there is some concern that it may be a health hazard. radon detectors are sold to homeowners worried about this risk, but the detectors may be inaccurate. university researchers placed 12 detectors in a chamber where they were exposed to 105 picocuries per liter (pci/l) of radon over 3 years. here are the readings given by the detectors:91.9 97.8 111.4 112.3 105.4 85.0 103.8 89.6 96.6 109.3 104.8 91.7 Assume (unrealistically) that you know that the standard deviation of readings for all detectors of this type is σ = 9. a. Give the 95% confidence interval for the mean reading μ for this type of detector. b. Is there significant evidence at the 5% level that the mean reading differs from the true value 105? State hypotheses and base a test on your confidence interval from (a). c. Calculate the power of this test against the…arrow_forward
- An isotope of the element erbium has a half-life of approximately 12 hours. Initially there are 14 grams of the isotope present. What is the rate of decay at t = 5.2 hours? O a. -7.1863 grams/hour O b. 0.8640 grams/hour O c. 0.5989 grams/hour O d. -0.5989 grams/hour O e. 7.1863 grams/hour O f. -0.8640 grams/hourarrow_forwardRadon-222 decays at a continuous rate of 17.3% per day. How much will 250 mg of Radon-222 decay to in 1 week?arrow_forwardgs Radon-222 has a half-life of 4.00 days. Given its mass 3.168 gram at a certain time, what was the sample's mass (in gram) before 0.7 month? 1 month is about 30.5 days.arrow_forward
- Radon is a colorless, odorless gas that is naturally released by rocks and soils and may concentrate in tightly closed houses. Since radon is slightly radioactive, there is some concern that it may be a health hazard. Radon detectors are sold to homeowners worried about this risk, but the detectors may be inaccurate. University researchers placed 30 radon detectors in a chamber where they were exposed to 105 picocuries per liter (pCi/l) of radon over 3 days. The sample average reading from the 30 radon detectors was 102.87 pCi/l and the sample standard deviation was 4.9 pCi/l. Are the researchers able to conclude at the 5% significance level that the average reading differs from the true value of 105? To test: Ho: (Click to select) (Click to select) : vs. Ha: ( (Click to select) : (Click to select) Test Statistic (Round to three decimals): (Click to select) p-value (Round to three decimals): Conclusion: At a =[ (Click to select) : since p-value (Click to select) a. We have (Click to…arrow_forwardRadon is a colorless, odorless gas that is naturally released by rocks and soils and may concentrate in tightly closed houses. Since radon is slightly radioactive, there is some concern that it may be a health hazard. Radon detectors are sold to homeowners worried about this risk, but the detectors may be inaccurate. University researchers placed 30 radon detectors in a chamber where they were exposed to 105 picocuries per liter (pCi/l) of radon over 3 days. The sample average reading from the 30 radon detectors was 102.87 pCi/ and the sample standard deviation was 4.9 pCiA. Are the researchers able to conclude at the 5% significance level that the average reading differs from the true value of 105? To test: Ho u vs. Ha Test Statistic (Round to three decimals) (Click to select) p-value (Round to three decimals) Conclusion: At a = evidence to conclude that the Click to select) pCiA. KClick to select) since p-value (Click to select) M a. We have KClick to select) V reading (Click to…arrow_forwardVanadium-48 has a half-life of about 16 days. Suppose that we have 21 grams of Vanadium-48. a) Find the decay rate. Round to 4 decimal places. b) For how many days will 14.1 grams of Vandium-48 be left? Round to 1 decimal place.arrow_forward
- 6 (8) Strontium-90 is a radioactive isotope with a half-life of 29 years. Strontium-90 is a major component of the fallout from nuclear testing. Suppose that approximately 10 kg of Strontium-90 was released into the environment around the Alamagordo test site in 1961. How much undecayed Strontium-90 remains today? Lab8 surface weat..pdf JoanneCarbonell.pdfarrow_forward18.2 Well water having a total hardness of 300 mg / L as CaCO , is softened by split treatment . A zeolite bed takes 3/4 of the total flow and produces water at a hardness of 3 mg / L . as CaCO , One - fourth of flow is directly mixed with the softened water . The zeolite bed has 28.3 m² resin capacity . The water softening capacity of the resin is 62 kg / m³ total hardness as CaCO ,. Exhausted resin is regenerated by 98 percent pure NaCl solution . The salt consumption is three times the theoretical amount and used as 4 percent salt solution . Calculate ( a ) regeneration period if 950 m³ per day of water is passed through the softener , ( b ) the hardness of the fin ishod water , and ( c ) salt consumption per regeneration cyclearrow_forwardOf an initial amount of 8000 g of lead-210, how much will remain in 160 years? Lead-210 decays at a rate of 3.15%/yr. (Round to one decimal place as needed.) DUHDarrow_forward
- Algebra & Trigonometry with Analytic GeometryAlgebraISBN:9781133382119Author:SwokowskiPublisher:Cengage