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Radioactivity
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Questions (550)
In a lab experiment, the decay of a radioactive isotope is being observed. At the beginning of the first day of the experiment
4 answers
asked by
Anonymous
2,237 views
Which radioactive sample would contain the greatest remaining mass of the radioactive isotope after 10 years?
A. 2.0 grams of 198
6 answers
asked by
Sanjay
5,934 views
Consider a radioactive sample with a half-life of one week. How much of the original sample will be left at the end of the
7 answers
asked by
Tracee
5,799 views
The half-life of a certain radioactive sub- stance is 8 hrs. There are 5 grams present initially. Which of the following gives
4 answers
asked by
Anonymous
950 views
If 18g of a radioactive substance are present initially and 8 yr later only 9 g remain, how much of the substance will be
4 answers
asked by
Sasha
5,917 views
sodium-24 has a half-life of 15 hours how much of a 20 gram sample would remain after 30 hours? and how do you solve this?
4 answers
asked by
victoria
2,360 views
the half time of a radioisotope is found to be 4.55 minutes. if the decay follow first order kinetics. what percentage of
4 answers
asked by
Linda Nnenna
2,202 views
Iodine 131 is a radioactive isotope. After 4.00 days, 70.8% of a sample of 131I remains.What is the half life of 131I?
4 answers
asked by
Natalie
4,659 views
In 4 years, 30% of a radioactive element decays. Find its half-life. (Round your answer to one decimal place.)
_____ yr
4 answers
asked by
Dee
1,559 views
The half-life for the radioactive decay of calcium-47 is 4.5 days.If a sample has an activity of 4.00uCi after 13.5 days, what
4 answers
asked by
Shay
2,795 views
Cobalt-60 is a strong gamma emitter that has a half-life of 5.26 yr. The cobalt-60 in a radiotherapy unit must be replaced when
4 answers
asked by
hannah
3,267 views
A radioactive substance decays exponentially. A scientist begins with 130 milligrams of a radioactive substance. After 20 hours,
4 answers
asked by
Jhon
3,443 views
1) The number of radioactive nuclei in a particular sample decreases over a period of 15 days to one-seventeenth the original
4 answers
asked by
Sandhya
2,021 views
Half life of radium is 44 years.The sample will reduce to 50% of its orignal value after how many years?
4 answers
asked by
Salman
656 views
the half life of isotope X is 2.0 years how many years would it take for 4.0 mg sample of X to decay and have .50 mg of it
3 answers
asked by
vanessa
2,805 views
If the half-life of a certain radioactive substance is 2000 years, estimate how many years must elapse before only 35% of the
4 answers
asked by
james
1,274 views
A radioisotope has a half-life of 4 days. How much of a 20-gram sample of this radioisotope remains at the end of each time
4 answers
asked by
Stephanie
3,939 views
A simple of radium weight 1000g. How long will it take to decay to 125g if its half life is 1620 years??
6 answers
asked by
Charles
843 views
Technetium-99m, an important radionuclide in medicine, has a half-life of 6.0 hours. What percentage of a sample of
4 answers
asked by
Anonymous
4,158 views
A radioactive substance decays according to the formula A=A0e^kt
where A0 is the initial amount of substance (in grams) A is the
5 answers
asked by
enhle
3,337 views
The half life of phosphorus -32 is 14.3 days. What percentage of an original samples radioactivity remains after 57.2 days?
4 answers
asked by
matt
2,956 views
As a sample of the radioactive isotope 131 I decays, its half-life
a)decreases b)increases c)remains the same
4 answers
asked by
Danny
4,212 views
The model for radioactive decay is y=y0e−kt. A radioactive substance has a half-life of 230 years. If 35 grams are present
4 answers
asked by
Heather
599 views
If, initially, there is 20 mg of gold-198 (198Au) (half-life = 2.696 days),
how many days does it take for less than 1 mg to
3 answers
asked by
anonymous
671 views
A radioactive sample initially contains N- atoms. After three half lives the number of atoms that
disintegrated is ?
3 answers
asked by
Majiri
752 views
The activity of a sample of Ba-137m has decreased by 75% from its initial activity after 5.10 minutes. What is the half-life of
3 answers
asked by
William
657 views
after six half-lives what percentage of a radioactive sample will remain?
a) 0%-1% b) 1%-3% c) 3%-6% d) 6%-10%
16 answers
asked by
victoria
5,023 views
32P is a radioactive isotope with a half-life of 14.3 days. If you currently have 48.1 g of 32P, how much 32P was present 3.00
3 answers
asked by
Anonymous
3,372 views
A building has become accidentally contaminated with radioactivity. The longest-lived material in the building is strontium-90.
3 answers
asked by
andrew
1,562 views
Why does the emission of an alpha particle always result in transmutation?
- Energy is released from the nucleus of the atom.
3 answers
asked by
Help
1,044 views
Tritium decays by a first order process that has half-life of 12.5years. how many years will it take to reduce the radio
3 answers
asked by
Assignment 3
1,160 views
If Radium-223 has a half life of 10.33 days, what time duration would it require for the activity associated with this sample to
3 answers
asked by
Christine
871 views
Suppose a patient is given 140mg of I−131, a beta emitter with a half-life of 8.0 days.
Assuming that none of the I−131 is
4 answers
asked by
TlP
2,394 views
What is the activity of a 18.9 μCi sample of carbon-14 in becquerels?
3 answers
asked by
ACDub
2,139 views
The half-life of radioactive strontium-90 is approximately 31 years. In 1960, radioactive strontium-90 was released into the
3 answers
asked by
Brandon
1,177 views
The half-life of phosphorus-32 is 14.26 days. The decay constant is k=4.86×10−2/days. If you accidentally spill phosphorus-32
4 answers
asked by
Anonymous
2,282 views
Strontium-85, used for bone scans, has a half-life of 64 {\rm d}.How long will it take for the radiation level of strontium-85
3 answers
asked by
Help!!
1,670 views
Twenty percent of a radioactive substance decays in ten years. By what percent does the substance decay each year?
4 answers
asked by
katrina
5,355 views
The half-life of a radioactive isotope is 10 days. If 3.2 kg are present now, how much was present 30 days previous?
5 answers
asked by
Michelle
486 views
The term radioactive is used to describe?
material that is explosive and is used in bombs any material that causes cancer an
3 answers
asked anonymously
52 views
If 70% of a radioactive element remains radioactive after 400 million years , then what percent remains radioactive after 600
3 answers
asked by
Alexus
1,132 views
The term radioactive is used to describe material that is explosive and is used in bombs any material that causes cancer an
3 answers
asked anonymously
57 views
Find the half-life of a radioactive element, which decays according to the function A(t)=A0e−0.0303t, where t is
3 answers
asked by
Shelby
71 views
Radium-223 has a half-life of 11.4 days.Approximately how long would it take for the activity of a sample of 223Ra to decrease
2 answers
asked by
Josh
965 views
Determine the total time that must elapse until only ¼ of an original sample of the radioisotope Rn-222 remains unchanged.
3 answers
asked by
Caio
1,159 views
If 12 % of a radioactive substance decays in 7 hours, what is the half-life of the substance?
Carry out all calculations exactly,
3 answers
asked by
liv
1,232 views
A radioactive substance is found to register 1000 counts per second on a Geiger counter. Twenty-four hours later it registers
3 answers
asked by
Owen
1,816 views
A certain radioactive isotope has a half-life of one hour. At noon, 100g of the material is present. How much of the original
3 answers
asked by
Sara
961 views
if the half life of a radioactive isotope is 80 hours how long would it take for 75% of the isotope to decay
3 answers
asked by
Anonymous
259 views
A scientist has 37 grams of a radioactive substance that decays exponentially. Assuming k=-0.3,how many grams of radioactive
3 answers
asked by
Marissa
1,274 views
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