Search: A radioactive elem..

Number of results: 593

science
I need a picture that describes radioactive decay, fussion and fision. Someone said that they would give me a link earlier but they didnt. Thank you! This website helps me out so much.
Thursday, January 15, 2009 at 5:05pm by Amy

Science
If a 20 gram sample of a radioactive substance has a half-life of 6000 years, how many grams would be present after 18000 years?
Wednesday, December 5, 2012 at 4:21pm by Owen

ALGEBRA
You have 480 grams of a radioactive kind of tin. If its half-life is 10 days, how much will be left after 30 days?
Wednesday, March 21, 2012 at 12:59pm by Anonymous

physics
Fluorine 20 is radioactive and Na 23 is not None of the reasons listed apply. F-20 just has more neutrons than the nucleus "needs"
Friday, September 17, 2010 at 9:54pm by drwls

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?
Monday, March 30, 2009 at 1:16am by mike

Chemistry
The nuclide 12 N 7 is unstable. What type of radioactive decay would be expected??? my guess is either gamma or beta. are either of those correct?
Tuesday, March 4, 2008 at 5:25pm by Jonathan

Chemistry please check
Ok except for #1. U is a radioactive element, naturally. There is a series for U-238, another series for U-235, and a third for Th-232. All end in Pb.
Friday, February 15, 2008 at 11:35pm by DrBob222

chemistry
use logic and simple math to determine how long it will take for a sample of potassium- 42 to decay from 8mg to 0.25mg if the half-life of this radioactive isotope is 124 hours
Tuesday, October 12, 2010 at 8:29pm by jay 1

Physics
In the radioactive formula 235 U → 235 Np + X, what does X represent 92 93 A. An Alpha Particle B. A positron C. An electron D. A gamma ray Please help ASAP!!! Thank you :D
Friday, June 3, 2011 at 4:32pm by J. J.

math
The decay of 333 mg of a radioactive substance is given by A(t) = 333e-0.024t, where t is time in years. Find the amount left after 17 years.
Friday, April 8, 2011 at 7:17pm by allison

Calculus
A certain radioactive material decays exponetially. The percent, P, of the material left after t years is given by P(t)= 100(1.2)^-t a)Determine the half life of the substance
Tuesday, April 13, 2010 at 7:43pm by lala

9th grade math
Here is a causal relatlionship. The amount of radioactive decayed products depends on the time since it was formed. Amount=OriginalAmount* e^(t/k) where k is a constant.
Thursday, March 5, 2009 at 8:20pm by bobpursley

Chemistry
Tc-99 is a radioactive isotope that decays by beta emission and is used by radiologists in the diagnosis of liver disease. Its decay behavior is shown by the activity-time table. What is its half-life?
Saturday, December 10, 2011 at 11:49pm by Jennifer

Alg2
Radioactive iodine is used to determine the health of the thyroid gland. It decays according to the equation y=ae -0.0856t where t is in days. Find the half-life of this substance. Round to the tenths place.
Thursday, December 8, 2011 at 7:37pm by Rock

Physics
This website doesn't post correct :/ In the radioactive formula 235 U → 235 Np + X, what does X represent 92 93 A. An Alpha Particle B. A positron C. An electron D. A gamma ray
Friday, June 3, 2011 at 4:20pm by J. J.

Physics
It got posted incorrectly: In the radioactive formula, 235/92 U → 235/93 Np = X, what does X represent A. An alpha Particle B. A positron C. An electron D. A gamma ray
Friday, June 3, 2011 at 4:20pm by J. J.

statistics
The average number of radioactive particles passing through a counter during 1 millisecond in a lab experiment is 4. What is the probability that more than 2 milliseconds pass between particles?
Wednesday, February 10, 2010 at 10:32pm by ashley

college
The average number of radioactive particles passing through a counter during 1 millisecond in a lab experiment is 4. What is the probability that more than 2 milliseconds pass between particles?
Wednesday, February 10, 2010 at 9:09pm by ashley

chemistry
What are some applications of Nuclear Chemistry in Medicine? So far I've found - X-rays - Radioactive tracers - Gamma radiation can be used to treat cancer and other diseases
Tuesday, March 11, 2008 at 8:05pm by william

Math/Radioactive Dating
I got your answer as well. Teachers do make mistakes. I make about 2 per day, but my wife tells me I make more than that.
Saturday, February 19, 2011 at 5:56pm by Reiny

Science
Half-life T is the time during which the number of decaying species decreases by half Decay Law N=Nₒ•exp(-λ•t) Decay constant λ=ln2/T. Half-life T is the time during which the number of decaying species decreases by half If t=T, then N= N&...
Monday, July 16, 2012 at 4:50am by Elena

College algebra
The radioactive element has a half-life of about 28 years and sometimes contaminates the soil. After 47 years, what percentage of a sample of the elements remain?
Sunday, May 12, 2013 at 4:20pm by Taylor

Physical Science- Help Please!
Suppose that you are given a 100 gram sample of a radioactive substance with a half-life of 32 days. How many grams will be left after 192 days?
Wednesday, December 5, 2012 at 4:13pm by Molly

Physics
In the radioactive formula, 235 U → 235 Np = X, what does X represent 92 93 A. An alpha Particle B. A positron C. An electron D. A gamma ray Please help ASAP!!! Thank you very much!!
Friday, June 3, 2011 at 4:20pm by J. J.

Physical Science
The heat of volcanoes and hot springs comes from trace amounts of radioactive minerals found in the Earth's interior. Why isn't the same rock at the Earth's surface warm?
Monday, March 10, 2008 at 6:10pm by Rachel

Physical Science
I'm still working on getting a fireman to come out to the school to demonstrate a radioactive detector. No luck so far. This is for a project on Marie Curie. Any other suggestions would be greatly appreciated.
Friday, October 10, 2008 at 3:47pm by jules

elem alg
On a certain test, the student gets 3 points for each correct answer and loses 2 points for each incorrect answer. The test has 37 questions total. (no question can be lfet blank.) If x is the number of answers a students gets correct, write and express fro the students total ...
Thursday, March 10, 2011 at 12:11am by Vera

Environmental Science 11th grade
If half of a quantity of radioactive material decays in 10 years, in another 10 years?
Thursday, February 7, 2013 at 12:34pm by AM

precalculus
Twenty percent of a radioactive substance decays in ten years. By what percent does the substance decay each year?
Thursday, March 3, 2011 at 5:40pm by katrina

Chemistry
If the amount of radioactive iodine-123 in a sample decreases from 0.8 g to 0.1 g in 36.2 hours, what is the half-life of iodine-123
Sunday, April 17, 2011 at 10:22am by Sara

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!
Friday, June 18, 2010 at 9:49am by Marie

chemistry
if the amount of radioactive iodine-123 in a sample decreases from .400g to .100g in 26.2 hours, what is the half-life of iodine-123
Thursday, April 18, 2013 at 7:23pm by j

Science
Radioactive decay law N =N₀exp(-λt)= =N₀exp(-ln2•t/T)= =20exp(-0.693•18000/6000) = 2.5 g
Wednesday, December 5, 2012 at 4:21pm by Elena

physical sciences
Eight is correct for the number of neutrons. Carbon-14 is an important isotope used for radioactive dating of carbon-containing organic matter. Its half life is 5568 years.
Tuesday, May 22, 2012 at 9:02am by drwls

physical science
A certain radioactive substance has a half-life of 1 hour. If you start with 1 gram of the material at noon, how much will be left at 3:00 P.M.? At 6:00 P.M.? At 10:00 P.M.?
Wednesday, November 2, 2011 at 10:08pm by cheryl

mathematics
what is the equation for exponetial decay(radioactive decay) and how to use the half life in the equation
Wednesday, November 2, 2011 at 4:30pm by anonymous

Elem. Ed.
It is confusing because it has given you two correct answers. It's a poorly written question. If you have the option, put down both answers. If you don't have the option of two answers, then I suggest you stick with B, learning to form letters. It may be that a child ...
Thursday, September 20, 2007 at 6:57pm by Ms. Sue

Chemistry
A 208 g sample of sodium-24 decays to 13.0 g of sodium-24 within 60.0 h. What is the half-life of this radioactive isotope?
Tuesday, December 11, 2012 at 11:08pm by Matthew

physics
The half life of a radioactive sample is 6.93 days.after how many days will only one -tenth of the sample be left behind?
Wednesday, August 1, 2012 at 2:37am by Mira

math
A 10 kg quantity of a radioactive isotope decays to 3 kg after 17 years. Find the decay constant of the isotope.
Thursday, February 3, 2011 at 1:45am by Eric

math
A 10 kg quantity of a radioactive isotope decays to 3 kg after 17 years. Find the decay constant of the isotope.
Thursday, February 3, 2011 at 1:44am by Eric

Pre calc
If 250 mg of a radioactive element decays to 200 mg in 48 hours, find the half-life of the element
Wednesday, April 28, 2010 at 10:06pm by Dom

Science
How much of a radioactive material with a half-life of 12,000 years is left after 36,000 years of decay?
Friday, April 17, 2009 at 1:29pm by Angie

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
Thursday, July 12, 2012 at 7:23pm by eric

chm
An unknown radioactive substance has a half-life of 3.20 . If 34.8 of the substance is currently present, what mass was present 8.00 hours ago?
Friday, February 10, 2012 at 12:23am by cp

Chemistry
I can't find it anywhere on the web but I think the number of half-lives at which a radioactive isotope is no longer a threat (from the radioactivity) is 10 half-lives.
Monday, November 16, 2009 at 7:08pm by DrBob222

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?
Wednesday, May 21, 2008 at 5:51am by ronny

PHYICS
Pick the radioactive isotope in each set 14/7 N OR 23/13 AL EXPLAIN A)its atomic number is greater than 83 B)it has fewer n than p in the nucleus C)it is an odd-odd nuclide none of the above
Saturday, September 18, 2010 at 11:51am by Ashley

physics
Pick the radioactive isotope in each set 23/11 na or 20/9 f explain why a)its atomic number is greater than 83 b)it has fewer n than p in the nucleus c)it is an odd-odd nuclide none of the above
Friday, September 17, 2010 at 9:54pm by Ashley

phyics
Pick the radioactive isotope in each set. 23/11 20/9 Explain your choice. a)its atomic number is greater than 83 b)it has fewer n than p in the nucleus c)it is an odd-odd nuclide none of the above
Friday, September 17, 2010 at 4:20pm by ashley

physics
Suppose 32000 radioactive nuclei are in a sample. About how many remain after two days if the half-life is 22 hrs? What is the initial activity of the sample in decays per minute?
Tuesday, May 5, 2009 at 10:06am by Anonymous

College Algebra
The half-life of a radioactive material is about 34.6 years. How much of a 1-gram sample of the material is left after 30 years?
Saturday, October 20, 2012 at 12:21am by Anonymous

Chemistry
You can go to www.webelements.com, click on the element and scroll down the left side to isotopes. There you can view the natural and radioactive isotopes of the element.
Saturday, September 15, 2012 at 1:31pm by DrBob222

Pre Calculus
Exponential growth and decay find the half life of a radioactive substance if 220 grams of the substance decays to 200 grams in 4 years?
Tuesday, October 25, 2011 at 1:40am by Josh

Elem. Ed.
I AM A PARENT,I THINK THE TEACHER NEEDS TO TAKE CHARGE OF HER OWN CLASS ROOM AND WHEN THE TEACHER FEELS ITS TIME TO GO.THAN ITS TIME TO GO,US PARENTS STICK AROUND TO MAKE OUR SELVES FEEL BETTER EVEN WHEN OUR CHILDREN ARE FINE,ITS HARD TO SAY GOOD BYE,SO TELL US WHEN YOU FEEL ...
Friday, May 4, 2007 at 7:52am by mrs.north

ms sue help
can u check my answer and check my answer on another? 4. _____ is measured in half-lives. *Radioactive decay Absolute age Uniformitarianism Carbon-14 I thinks its a
Tuesday, November 20, 2012 at 1:16pm by Jman

ap calculus
suppose that the amount in grams of a radioactive substance present at time t (in years) is given by A (t) = 160e-.70t. Find the rate of decay of the quantity present at the time when t = 4
Sunday, December 2, 2012 at 9:07pm by steve b

chemistry
A radioactive sample contains 2.45g of an isotope wiht a half life of 3.8 days. How much of the isotope in grams remains after 11.4 days? please explain
Saturday, November 26, 2011 at 11:38am by Monique

Elem. Ed.
Which requires a child's coordination with speech and movement? A. puppet play and storytelling B. finger plays and flannel boards C. flannel boards and storytelling D. finger plays and puppet play I am thinking (A) puppet play and storytelling, but not real sure. Please,...
Tuesday, September 18, 2007 at 7:21pm by Anonymous

ALGEBRA
Suppose that a certain radioactive substance has a half-life of 20 years. If there are presently 2400 milligrams of the substance, how much, to the nearest milligram, will remain after 70 years?
Wednesday, March 21, 2012 at 12:59pm by Anonymous

chemistry -- radioactive decay
k = 0.693/t1/2 Solve for k. ln(No/N) = kt No = 150 N = solve for this k from above. t = hours for t and solve for N in grams.
Tuesday, September 18, 2012 at 11:53pm by DrBob222

Earth Science
Describe how Earth would be different today if it contained no radioactive material. What would the consequences be for the Earth’s interior layers?
Thursday, December 2, 2010 at 6:28pm by Jack

Earth Science
Describe how Earth would be different today if. It contained no radioactive material. What would the consequences be for the Earth's interior layer?
Wednesday, September 30, 2009 at 1:00am by Breanna

science
Perhaps you will find the answer in one of these sites: http://www.google.com/search?hl=en&client=firefox-a&rls=org.mozilla:en-US:official&hs=aRq&sa=X&oi=spell&resnum=0&ct=result&cd=1&q=heaviest+element+with+1+isotope+%26+is+not+radioactive&...
Sunday, January 25, 2009 at 12:55pm by SraJMcGin

physic
b) •It is done by Carbon dating. Carbon is the basic basic building block of life and has an amazing memory. Rays of the Sun which are radioactive enter our atmosphere and collide with Nitrogen atoms to create the radioactive isotope, Carbon-14. •We have both Carbon-...
Saturday, April 16, 2011 at 6:55am by justin

Elem. Ed.
Portfolios are a collaborative effort in that: A. children,teachers,and specialists can all choose samples to include in a portfolio. B. each item in the porfolio should be discussed with parents before it is included. C. teachers must have input from other teachers in the ...
Tuesday, April 10, 2007 at 8:45pm by Keisha

Pre-Cal
The radioactive isotope of Carcon (^14C)has a half life of 5730. What is the decay constant of ^14C? If we start with a sample of 1000 carcon nuclei, how many will be left in 22920 years time?
Thursday, April 8, 2010 at 1:43pm by Moe

12th grade
The radioactive isotope of Carcon (^14C)has a half life of 5730. What is the decay constant of ^14C? If we start with a sample of 1000 carcon nuclei, how many will be left in 22920 years time?
Thursday, April 8, 2010 at 12:34pm by Moe

classroom instruction
• Write a 200- to 300-word response describing how you might teach this concept to students in a lower elementary grade and to students in a middle school grade. i picked problem solving i have this so far. i guess for each grade level (elem and middle school) i would ...
Friday, March 19, 2010 at 9:18pm by scooby

Physics
University students, studying the activity of a particular radioactive isotope which had a half-life of 12.0 hours. If the original activity of the sample was 448 kBq, what would the activity be 3.00 days later?
Sunday, May 16, 2010 at 8:59am by Anonymous

Chemistry
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 days ago?
Sunday, June 10, 2012 at 4:11am by Anonymous

chemistry
a radioactive fission product of nuclear explosions and sccidents is often iodine 131 which becomes distributed in the atmosphere. this falls upon the ground and is absorbed by plants. explain how this radiation could eventually beome concentrated in the human body and cause ...
Monday, February 4, 2008 at 6:14pm by Amanda

chem
a radioactive fission product of nuclear explosions and sccidents is often iodine 131 which becomes distributed in the atmosphere. this falls upon the ground and is absorbed by plants. explain how this radiation could eventually beome concentrated in the human body and cause ...
Sunday, February 3, 2008 at 7:55pm by Amanda

physic
They are man-made radioisotopes of heavy elements that are not part of the natural radioactive decay series that start with uranium or thorium. In other words, they only found on Earth if they were created in an accelerator, nuclear explosion, or nuclear reactor.
Tuesday, March 9, 2010 at 6:50am by drwls

Elem. Ed.
Please let me know if you agree with my answers to these two questions. 1.Hannah's mother said,"Hannah is such a "pencil-and-paper" kid." It is likely that Hannah: A. will be an artist. B. will learn to write,forming her letters perfectly. C. will be a ...
Thursday, September 20, 2007 at 6:57pm by Anonymous

chemistry
Rates of chemical reactions usually depend on temperature and pressure. However, half-life of all radioactive elements is independent of both T and p. How can these decay rates be independent of T if we beleive in the Arrhenius equation?
Tuesday, July 27, 2010 at 8:56pm by Jin

Physics
A certian radioactive isotope has a half-life of 1 hour. If you start with 1 gram of the material at noon, how much of the original isotope will the sample contain at 3 pm? At 6 pm? At 10 pm?
Saturday, November 17, 2007 at 12:41pm by Judy

Physical Science
This reference may be useful. http://www.nrc.gov/about-nrc/radiation/sources.html You may have some difficulty finding a radioactive source with a half-life short enough to measure. Most are used in nuclear medicine, with carefully limited distributiuon. My son once did a ...
Tuesday, November 13, 2007 at 5:46am by drwls

science
The thermal energy of volcanoes and natural hot springs comes from trace amounts of radioactive minerals in common rock in the Earth's interior. Why isn't the same kind of rock at the Earth's surface warm to the touch?
Wednesday, January 30, 2008 at 7:57pm by Ashton

Physics
A half-life is how long it takes for a radioactive isotope to decay by half. At 2 PM, you will have .5 grams of the material. Each hour thereafter, divide the material by half to see how much remains.
Saturday, November 17, 2007 at 12:41pm by Michael

Chemistry
Each of the following nuclides is known to undergo radioactive decay by production of a beta particle, ^0_-1e. Write a balanced nuclear equation for each process. (Use 'e' for an electron, 'p' for a positron, and 'n' for a neutron. Omit states-of-matter...
Saturday, November 27, 2010 at 3:54pm by Jane

science
Some lesser sources are windblown dust (especially in northern China), volcanic eruptions and radioactive radon from the ground that gets trapped inside buildings. The photolysis of organic matter released by trees and spilled gasoline also creates a haze.
Monday, September 22, 2008 at 7:57am by drwls

Chemistry
The half-life for radioactive decay of 14C is 5730 years (it emits β-particles with energy of 0.16 MeV). An archaeological sample contained wood that had only 72% of the 14C found in living trees. What is its age?
Thursday, April 8, 2010 at 4:02pm by Zoa

Elem. Ed.
Which would be a way for a teacher to help students learn about aesthetics in an appropriate way? 1. creating a sensory-rich enviroment (or) 2. exposing children to convegent ideas creating a sensory rich enviroment would be the best appropriate way. Am I correct? Conventional...
Sunday, April 8, 2007 at 6:48pm by Keisha

chemistry
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 was the initial activity of the sample?
Wednesday, September 26, 2012 at 2:30pm by Shay

college
a certain radioactive isotope has a half life or 850 years.how many years would it take for a given amount of this isotope to decay to 70% of that amount?
Thursday, December 2, 2010 at 9:53am by Kiesha

Elem. Ed.
Would you please help me with this question? Charlie does not come to group time on his own. While he is there, he does not participate or respond. Which would be best for the teacher to do? A. insist he participate since this is the only way he will learn. B. continue to ...
Sunday, September 16, 2007 at 3:17pm by Anonymous

physics
After 1.84 days, the activity of a sample of an unknown type radioactive material has decreased to 85.8% of the initial activity. What is the half-life of this material? (in days)
Sunday, June 3, 2012 at 1:43am by andrew

Chemistry
A certain radioactive element has a half life of 1 h. If you start with a 1-g sample of the element at noon, how much is left at 3:00 PM? At 6:00PM? At 10:00 PM?
Friday, October 8, 2010 at 12:20pm by Jennifer

Calculus
The amount A in grams of radioactive plutonium remaining in a 20-gram sample after t days is given by the formula A=20*(1/2)^(t/140). At what rate is the plutonium decaying when t=2 days?
Tuesday, November 30, 2010 at 6:29pm by Sara

physics ASAP
Can someone give me an example of how to use this formula: Obtain three half-life (T0.5) times from the graph. Average them.(T0.5)av. Or is there a web site i can go to that shows all steps to using pennies for radioactive decay experiment? .
Sunday, November 18, 2007 at 2:45pm by Will

Physics
Can someone give me an example of how to use this formula: 15.Obtain three half-life (T0.5) times from the graph. Average them.(T0.5)av. Or is there a web site i can go to that shows all steps to using pennies for radioactive decay experiment? .
Thursday, November 15, 2007 at 1:25pm by Will

Science
Radioactive carbon-14 dating has determined that a fossil is 5.7 x 10 to the third power years old. What is the total amount of the original Carbon-14 still present in the fossil?
Wednesday, March 24, 2010 at 4:43pm by Gina

Biology
I think B. Plutonium is radioactive. A mutation that changes a single base in a region of noncoding DNA would not have any or would have minimum effect on a cell. And most of the stuff that living beings consume are carbon based.
Monday, February 25, 2013 at 10:41pm by Devron

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