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Strontium-90
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COLLEGE ALGEBRA CUSTOM TEXT WITH ALEKS 3
- Initially, 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_forwardAn 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 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_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/ 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_forwardThe half-life of radioactive cobalt is 5.27 years. Suppose that a nuclear accident has left the level of cobalt radia- tion in a certain region at 100 times the level acceptable for human habitation. How long will it be until the region is again habitable? (Ignore the probable presence of other radioactive isotopes.)arrow_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_forward
- radon 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_forwardThe half-life of Radium-226 is 5 years. How much of an initial 170 g sample will remain after 22 years? O 199.01 O 8.05 O 21368.91 O:1.35 0:3589.06arrow_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_forward
- Algebra & Trigonometry with Analytic GeometryAlgebraISBN:9781133382119Author:SwokowskiPublisher:Cengage