Substance A is being observed and it was recorded that its half – life is 6 months. Determine the amount of substance A that has been disintegrated after a year.

Q: Mantles for gas lanterns contain thorium, because it forms an oxide that can survive being heated to…

A: Given: The half life time of thorium is t1/2=1.405×1010 y. The mass of thorium in lantern is m=300…

Q: What is the activity of a 20 ng sample of 92Kr, which has a half-life of 1.84 s?

A: In 92gm of 92Kr, will contain 6.02×1023 atoms of 92Kr.

Q: How much is the mass of the sample in grams of Po-218 that has an activity of 5.00 x 1019 Bq? The…

A: Given Activity = rate of disintegration = 5 × 1019 Bq = 5 × 1019 disintegration/second Half life =…

Q: Example (3) : 0.2 gram of pure potassium 40 ("K) emit about 10 beta rays per second .Estimate its…

A: Mass , m = 0.2 gm  Atomic weight = 40  To find = Half life

Q: The charred bones of a sloth in a cave in Chile represent the earliest evidence of human presence at…

A: Given, Specific activity of bone (N)=5.22 disintegrations per minute per gram of carbon (d/min.g).…

Q: 3. An ancient club is found that contains 150 g of pure carbon and has an activity of 5.5 decays per…

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Q: Tritium has a half-life of 12.3 years. Suppose there are initially 1.0 x 1012 tritium atoms. (a)…

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Q: archaeologist sometime in the future analyzes the iron used in an old building. The iron contains…

A: half life of Ni -63  t/2 = 92 years LET x half life passed (N0 /2)X =( N0 / 128 ) = (N0 /2)7  X = 7…

Q: The relatively scarce naturally occurring calcium isotope48 Ca has a half-life of about 2×1016 y .…

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Q: Mantles for gas lanterns contain thorium, because it forms an oxide that can survive being heated to…

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Q: The main dangerous radioactive material left over after the Chernobyl disaster is Caesium-137. The…

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Q: A thyroid cancer patient is given a dosage of 131I (half-life = 8.1 d). What fraction of the dosage…

A: The objective of the question is to find out the fraction of the dosage of Iodine-131 that will…

Q: 1) how many grams of material remain when you start with 16g and the half-life number is 3 ?

A: Half Life number = t/T = 3 ( where T = half life and t = time of observation ) Initial mass of…

Q: A sealed box was found which stated to have contained an alloy composed of equal parts by weight of…

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Q: Mantles for gas lanterns are made of thorium, because it forms an oxide that can survive being made…

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Q: Calculate the radioactivity of 0.5mg of cobalt 56 in units of curie? Its radioactivity is 50 days,…

A: Given data: The sample amount of cobalt is  m=0.5 mg=0.5×10-3 g The atomic mass of cobalt is A= 56 g…

Q: A radioactive substance is found to register 5000 counts per second on a Geiger counter.…

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Q: Suppose Radon gas is trapped in a basement after renovations. The half life of radon gas Is 3.8235…

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Q: If the unit for atomic mass were defined so that the mass of 1H were exactly 1.000 000 u, what would…

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Q: An artifact classified as charcoal, found in a site at Epirus, Greece, is found to have a 14C…

A: initial radioactivity(Ro)=0.255 counts per second final radioactivity(R)=4.36 X 10-2 counts per…

Q: A radioactive substance has a half-life period of 30 days. What is the disintegration constant?

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Q: If 16 g of radon with a half-life of 4 days is present in a balloon at t = 0, what is the mass of…

A: Most of the nuclei present are unstable in nature. They try to gain stability by disintegrating…

Q: The half-life of iodine-131 is 8 days. How long does it take for the initial activity of 4500 kBq /…

A: half life of iodine 131 = 8 days Initial activity (Ao) = 4500 kBqm3Final activity (A) = 65 kBqm3

Q: Potassium-argon dating is used to measure the age of rocks formed from cooled lava by determining…

A: The radioactive dating of rocks formed from cooled lava is determined by using parallel decay of…

Q: Suppose that a sample of lead-214 initially has an activity of 100 Ci. The half-life of lead-214 is…

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