Sunday
April 20, 2014

Search: 2. Explain how radioactive decay has always warmed the Earth from the inside, and nuclear fusion has always warmed Earth from the outside

Number of results: 24,932

Physics
Hi Radioactive decay - A radioactive nuclide has a decay constant of - 10^-6 s-1 what is its half life ? I have come up with is IN (2) / 0.000001 s-1 = 693147.18055 which iam having troube working into real figures Can anyone help please .. thanks
Saturday, August 24, 2013 at 8:27am by Freddo

Physics ...
Hi Radioactive decay - A radioactive nuclide has a decay constant of - 10^-6 s-1 what is its half life ? I have come up with is IN (2) / 0.000001 s-1 = 693147.18055 which iam having troube working into real figures Can anyone help please .. thanks
Saturday, August 24, 2013 at 3:44pm by Freddo

Science- Radioactive Dating
Which of the following statements about radioactive dating is true? a. Radioactive decay is the rate at which new atoms form. b. During radioactive decay, atoms break down, releasing particles or energy. c. The rate of decay of a radioactive element cannot be approximated. d. ...
Thursday, October 10, 2013 at 2:41pm by Anonymous

science
Which statement best explains why dating geologic materials from the Quarternary Period uses a different radioactive isotope than for materials from the cambrian Period? a. all rocks contain radioactive substances. b. some isotopes decay faster than others. c. not all isotopes...
Saturday, April 4, 2009 at 9:03pm by Angie

Chemistry
How many half lives will it take for a sample of a radioactive isotope containing 20000 radioactive nuclei to decay to 2000 radioactive nuclei
Tuesday, November 16, 2010 at 7:41pm by Dianne

Differential Equations
Model radioactive decay using the notation t = time (independent variable) r(t) = amount of particular radioactive isotope present at time t (dependent variable) -λ = decay rate (parameter) Note that the minus sign is used so that λ > 0 a) Using this notation, ...
Thursday, January 17, 2013 at 10:08pm by Quinn

MATH!
The mass of a radioactive substance follows an exponential decay model, with a decay rate of 5% per day. A sample of this radioactive substance was taken six days ago. If the sample has a mass of 3 kg today, find the initial mass of the sample. Round your answer to two decimal...
Thursday, March 15, 2012 at 8:53pm by Kim

science
A 10g sample of radioactive substances is lift to decay for five half-lives. How much of the radioactive substance remains?
Tuesday, February 19, 2013 at 3:51pm by mirian hernandez

Math - D.E.Q.
The half-life of a radioactive isotope is the amount of time it takes for a quantity of radioactive material to decay to one-half of its original amount. i) The half-life of Carbon 14 (C-14) is 5230 years. Determine the decay-rate parameter  for C − 14.
Tuesday, January 18, 2011 at 12:07pm by Justin

radioactive decay
What elements results if one of the neutrons is in a nitrogen neucleus is converted by radioactive decay into a proton? The atomic number goes from 7 to 8, while the atomic weight stays the same. An electron (beta-) is emitted from the nucleus. Actually, this process does not ...
Tuesday, June 28, 2005 at 3:20pm by Jarrad Schomaker

chemistry
yes, i do mean isotopes that undergo radioactive decay. However i do not really understand what this radioactive thing have to do with isotopes or unstable or stable.
Saturday, February 7, 2009 at 8:46am by Nabiha

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

Algebra
What are some real-life examples of exponential decay? Please help me think of some ideas...except radioactive decay.
Thursday, January 30, 2014 at 5:47pm by Anonymous

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

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

Math
You are talking about a radioactive substance-- one that emits radiation-- NOT a radio. The annual decay rate is what you multiply the number of radioactive atoms by to get the decay rate, k, in atoms per year. See http://hyperphysics.phy-astr.gsu.edu/hbase/nuclear/halfli2....
Tuesday, June 5, 2012 at 3:46am by drwls

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

science
during radioactive decay atoms of a radioactive element break down and change into other atoms of another element-all at once a) true b) false
Wednesday, December 11, 2013 at 12:56pm by victoria

Earth Science
1. Is it true that since energy cannot be created nor destroyed, the total energy of the river system remains constant? 2. What is the source of energy that powers the water cycle? a. sunlight insolation b. kinetic energy c. radioactive decay d. gravitational potential energy ...
Monday, November 24, 2008 at 1:08pm by John

science
Try some of the following links: http://search.yahoo.com/search?fr=mcafee&p=describe+how+radioactive+isotopes+decay Sra
Sunday, December 5, 2010 at 9:57pm by SraJMcGin

chemistry -- radioactive decay
suppose you have a 150 gram sample of radioactive decay god-191 which has a half- life of 3.4 hours. how many grams of gold will ramain after 10hrs ? after 24 hrs? answer : 10 hrs :10/3.4= 2.94 times 150*(1/2)^2.94 = 18.75 grams 24 hrs: 24/3.4 = 7.06 150*(1/2)^7.06= 1.12 right...
Tuesday, September 18, 2012 at 11:53pm by Maria

calculus
Carbon-14 is a radioactive substance produced in the Earth's atmosphere and then absorbed by plants and animals on the surface of the earth. It has a half-life (the time it takes for half the amount of a sample to decay) of approximately 5730 years. Using this known piece of ...
Friday, July 24, 2009 at 1:11pm by j

Science
Try some of the following links for information: http://search.yahoo.com/search?fr=mcafee&p=a+model+of+radioactive+decay+with+popcorn+kernals+ Sra
Sunday, March 20, 2011 at 12:55pm by SraJMcGin

8th Grade Earth Science Help?
Which of the following terms refers to the time it takes for one-half of the radioactive atoms in a sample of a radioactive element to decay? - relative age - absolute age - potassium-argon data - half-life** Is my answer correct?
Tuesday, January 14, 2014 at 7:05pm by Rainshine

science
Calculate the uranium ratios in the natural uranium decay chain using radioactive decay relationships. Compare to the value obtained using published natural abundances.
Saturday, January 29, 2011 at 3:59pm by Anonymous

chemistry
A particular radioactive substance has a half-life of 4 minutes. How long will it take for 250 g of this radioactive material to decay to less than 0.1g? 24 min 36 min 40 min 48 min 72 min I got 32 min but that not one of the choices. Please help
Monday, December 5, 2011 at 2:53pm by Anonymous

Algebra
A defective nuclear reactor is leaking radioactive iodine-131. The rate of decay of iodine-131is given by the function defined by A(t)=A_0 e^(-0.087t), where t is time in days. How long will it take any quantity of iodine-131 to decay to 25% of its initial amount?
Wednesday, June 19, 2013 at 3:06pm by AZ

Algebra 2 help...
A half life of a certain radioactive is 36 days. An initial amount of the material has a mass of 487 kg. Write an exponential function that models the decay of this material. Find how much radioactive material remains after 5 days. Round your answer to the nearest thousandth.
Friday, January 10, 2014 at 8:13pm by Maria

chemistry
Write a partial decay series for Po-214 undergoing the following sequential decays: , , , . Use e for an electron. Use the format +1 or -1 for charge. a)a decay b) decay c)a decay d) decay
Thursday, September 30, 2010 at 5:20pm by lisa

Calculus-Modeling Equations
An unknown radioactive element decays into non-radioactive substances. In 420 days the radioactivity of a sample decreases by 39 percent. 1.What is the half-life of the element? 2.How long will it take for a sample of 100 mg to decay to 46 mg?
Friday, March 6, 2009 at 12:08am by Kim

science
describe how radioactive isotopes decay
Sunday, December 5, 2010 at 9:57pm by kayla

Physical Science
What is an example of radioactive decay?
Thursday, October 13, 2011 at 1:35pm by Brooke

Math
A radioactive substance decays according to the formula Q(t) = Q0e−kt where Q(t) denotes the amount of the substance present at time t (measured in years), Q0 denotes the amount of the substance present initially, and k (a positive constant) is the decay constant. (a) ...
Saturday, April 5, 2014 at 10:05pm by Vanessa

Math
A radioactive substance decays according to the formula Q(t) = Q0e−kt where Q(t) denotes the amount of the substance present at time t (measured in years), Q0 denotes the amount of the substance present initially, and k (a positive constant) is the decay constant. (a) ...
Sunday, April 6, 2014 at 8:54pm by Vanessa

physis
Search: 2. Explain how radioactive decay has always warmed the Earth from the inside, and nuclear fusion has always warmed Earth from the outside.
Sunday, January 26, 2014 at 10:50pm by barbara

phys
Although most natural potassium nuclei are stable 39K (93.3%) or 41K (6.7%) nuclei, about 0.0117% are radioactive 40K nuclei, which have a half-life of 1.26 billion years. What fraction of all the potassium nuclei in your body will undergo radioactive decay in the next 1.04-...
Thursday, June 6, 2013 at 1:20am by Anonymous

earth
3. What can scientists learn from the rate at which radioactive elements decay?
Tuesday, December 10, 2013 at 6:34pm by Elizabeth

Chemistry
Pu-238 is radioactive by alpha-decay (half-life 87.7 y). Each decay releases 5.6 MeV of energy. Pu-238 is sometimes used to power space probes. If all the decay energy can be converted to electric power, what mass of Pu-238 would be required to power a 22 kW space probe for at...
Tuesday, October 15, 2013 at 8:44pm by Jane

chem
Pu-238 is radioactive by alpha-decay (half-life 87.7 y). Each decay releases 5.6 MeV of energy. Pu-238 is sometimes used to power space probes. If all the decay energy can be converted to electric power, what mass of Pu-238 would be required to power a 22 kW space probe for at...
Wednesday, October 16, 2013 at 8:21pm by Jane

Chemistry (PLEASE HELP)
"Nuclear fusion produces no long-lived radioactive by-products. " Perhaps it depends on wht you mean by 'long lived' and if only by-products from the actual fusion are considered. There are disposal considerations for radioactive waste from fusion. For info on fusion see the ...
Tuesday, April 19, 2011 at 7:58pm by DrRuss

chemistry
How long will it take for 25% of the C-14 atoms in a sample of C-14 to decay? The half-life for the radioactive decay of C-14 is 5730 years. If a sample of C-14 initially contains 1.1 mmol of C-14 , how many millimoles will be left after 2275 years?
Sunday, February 28, 2010 at 2:17pm by Anonymous

Science
How is nuclear radiation produced? What are 3 types of radioactive decay and how do they work? Thanks!
Friday, April 24, 2009 at 1:29pm by Lauren

Science
radioactive decay 212 RN----Azx----4He 86 2
Tuesday, March 6, 2007 at 3:25pm by shonna

Science
Need help with constructing a model of radioactive decay with popcorn kernals
Sunday, March 20, 2011 at 12:55pm by Kim

Science
3. What can scientists learn from the rate at which radioactive elements decay? (1 point)
Wednesday, November 6, 2013 at 10:19am by Nicole

Science
3. What can scientists learn from the rate at which radioactive elements decay? (1 point)
Wednesday, November 6, 2013 at 5:28pm by Nicole

science
Please check the following links and your spelling: http://search.yahoo.com/search?fr=mcafee&p=what+typ+of+radioactive+decay+results+in+u+ranium-238+becoming+thorium-234 Sra
Wednesday, December 15, 2010 at 9:05pm by SraJMcGin

chem
Complete the following radioactive decay problem. 234 4 U ---> He+ 92 2 how do i do this?
Friday, May 20, 2011 at 3:37pm by Alie

Problem
If an Elements has a half life of 20mins what is the radioactive decay of a 200gram sample?
Tuesday, June 11, 2013 at 4:47pm by Half life

Science
Radioactive substance decays so that after t years, the amount remaining, expressed as a percent of the original amount, is A(t)=100(1.6)^(-t). a) Determine the function A, which represent the rate of decay of the substance. b) what is the half-life for this substance? c) ...
Tuesday, March 6, 2012 at 11:03pm by jessica

chem
Write a partial decay series for Rn-220 undergoing the following sequential decays: (alpha decay), , (beta decay), . (Enter the mass number in the first raised box, the atomic number in the second lower box and the symbol of the element in the third box. Enter the nuclide...
Thursday, September 30, 2010 at 7:41pm by lisa

Physical Science
Alpha decay. example type of radioactive decay, in which an atomic nucleus emits an alpha particle, and thereby transforms (or 'decays') into an atom with a mass number 4 less and atomic number 2 less. Many other types of decays are possible.
Thursday, October 13, 2011 at 1:35pm by Angel

chemistry
You want to heat a satellite by radioactive decay of 238 plutonium. Assume you need heating of 200 Watts (J/s), how many Becquerel you need in your plutonium sample, if the decay energy of 238 plutonium is 5.593 MeV? (1 joule = 6.24 x 10^18 eV ) When will 1 mg of Pu be ...
Friday, November 19, 2010 at 12:22am by Anonymous

Chemistry - radioactive decay .
It decays by electron capture so it would be reduced to Pt. I don't know the half life.
Tuesday, September 18, 2012 at 11:45pm by DrBob222

Science
Half-life T is the time during which the number of decaying species decreases by half Decay Law N=Nₒexp(-λt) 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= Nₒexp(-λT...
Monday, July 16, 2012 at 4:50am by Elena

math
An unknown radioactive element decays into non-radioactive substances. In 100 days the radioactivity of a sample decreases by 64 percent. a)(a) What is the half-life of the element? half-life: b)How long will it take for a sample of 100 mg to decay to 51 mg? time needed:
Saturday, May 18, 2013 at 4:06am by Rachel

science
Hello! I need help with some Science things. 1. Where is a good place to find a picture that describes radioactive decay, fussion and fission/ 4. Scientists use the amount of radioactive isotopes found in rocks and fossils to calculate their ages. This process is called_____ 5...
Thursday, January 15, 2009 at 12:40pm by Amy

General chemistry
What is the decay constant for a radioactive isotope which decreases to 34% of its original value in 2.48 hours?
Tuesday, April 27, 2010 at 12:41pm by me

Pre Calculus
Exponential Growth and Decay Find the half-life of a radioactive substance that decays by 5% in 9 years.
Saturday, October 22, 2011 at 7:23pm by Josh

Science
Identify and describe the type of radiation emitted during the radioactive decay of the radioisotope xenon 135
Tuesday, May 21, 2013 at 7:49am by Olivia

Geology
Does this sound right? Describe your assigned method and how it is used to evaluate geologic time. My assigned method was Absolute Dating / Numerical Age. Absolute Dating / Numerical Age is the process that assigns a numerical age ( this tells how old a rock or fossil is);to a...
Tuesday, March 31, 2009 at 9:47am by A.W.

Science [Earth]
Can you please: 1. briefly explain the concept of radioactive decay and describe how it can be used to find the absolute age of rocks. 2. contrast relative age with absolute age and describe at least three methods of determining either. 3. compare advantages and disadvantages ...
Friday, May 8, 2009 at 3:11pm by xxx

advanced functions HELP!!!
Radioactive decay is the process by which an unstable element transforms into different element, typically releasing energy as it does so. For 500g of a radioactive substance with a half-life of 5.2 hours, the amount remaining is given by the formula M(t)=500(0.5) ^ t/5.2 a) ...
Wednesday, December 10, 2008 at 8:55pm by james

Chemistry - radioactive decay .
list 2 reason why this isotope of gold- 191 would not be a good substitute for making jewelry?
Tuesday, September 18, 2012 at 11:45pm by Maria

Physics
A radioactive substance decays from 2.0kg to 1.6kg in 156 days. How long would it take to decay to 1.1kg?
Wednesday, August 7, 2013 at 9:46am by Alice

science
Check these pictures. http://images.google.com/images?hl=en&ie=ISO-8859-1&q=radioactive+decay%2C+fussion+and+fision&btnG=Search+Images&gbv=2
Thursday, January 15, 2009 at 5:05pm by Ms. Sue

Calculus
[Exponential growth & decay] The half-life of radioactive strontium-90 is approximately 29 years. In 1965, radioactive strontium-90 was released into the atmosphere during testing of nuclear weapons, and was absorbed into people's bones. How many years does it take until only ...
Tuesday, October 6, 2009 at 8:08pm by Z32

pre-calculus
Given that the radioactive decay equation is q = 1250 e-0.05t, if t is in months, the amount of milligram present after 4 year is?
Sunday, March 4, 2012 at 5:10pm by romain

chemistry
The idea is to use an isotope of O or make O radioactive and use that to produce CO2 or H2O (that is make O different so you can find it). Then (if you made O radioactive) measure the glucose and the O2 and see if the O2 is radioactive or if the glucose is radioactive. Let's ...
Monday, April 15, 2013 at 12:04am by DrBob222

Chem 2
The half-life for the radioactive decay of U-238 is 4.5 billion years and is independent of initial concentration. a) How long will it take for 10% of the U-238 atoms in a sample of U- 238 to decay? b)If a sample of U-238 initially contained 1.91018 atoms when the universe ...
Thursday, July 21, 2011 at 9:55pm by Kristina

chemistry
Help plzzz Besides the major types of radioactive decay, there are two others: positron emission and electron capture. Compare and contrast positrons with electrons. Explain how positron emission works and how it causes transmutations. Explain how electron capture works ...
Friday, May 31, 2013 at 2:12pm by Help!!! Maddie

earth science
how does radioactive decay provide heat energy within the earth
Saturday, July 19, 2008 at 3:06pm by kate

chem
what changes in atomic number and mass number occur in a positron emmision of radioactive decay?
Monday, June 2, 2008 at 8:12pm by jerson

geology / science
the age of granite can be determind using radiometric dating, explain the basis for the determination of a 238 U- Pb radiometric date of 1120 Ma for a granite. I have as the answer 238 U decays to Pb with an experimental law, that is the amount of U and Pb in granite are ...
Wednesday, April 18, 2007 at 10:16am by bex

Physics
The decay process is explained better at http://en.wikipedia.org/wiki/Cobalt-60 Each Co-60 nucleus results in one beta electron and two gamma photons. That is three nearly simultaneous radioactive emission processes during the each transmutation, with a 5.27 year half life. ...
Thursday, November 20, 2008 at 4:55am by drwls

Calculuc
How do you set up this problem? The decay constant for the radioactive element cesium 137 is .023 when time is measured in years. Find its half-life.
Wednesday, August 22, 2012 at 9:28am by Jillian

Geology
If the decay constant for radioactive decay of ^40 K is λ = 5.543*10^(-10) / year, use this equation to calculate ages of the samples in the following table: t(1/2) = 0.693/λ 1)What is the half life of 40K? table -----Np --- Nd---- Nd/Np A)6439-----2303---0.358 B)...
Thursday, November 21, 2013 at 12:20pm by Maura

Physics
A radioactive substance decays from 2.0kg to 1.6kg in 156 days. What is the decay constant and the half life of the substance?
Tuesday, August 6, 2013 at 11:28pm by Alice

Algebra; PLEASE HELP. D:
Do you know what an exponential decay function is? For an example, read about radioactive decay. http://math.usask.ca/emr/examples/expdeceg.html
Thursday, February 2, 2012 at 7:47pm by drwls

Chemistry
6CO2 + 6H2O ==> C6H12O6 + 6O2 Make O in CO2 radioactive; see where the radioactive O is at the end. Make O in H2O radioactive; see where the radioactive O is at the end.
Sunday, April 14, 2013 at 11:52pm by DrBob222

chemistry
a radioactive material is undergoing nuclear decay. After 40 minutes, 25% of the sample remains. What is the half-life of the sample
Saturday, August 27, 2011 at 9:00am by marjani

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

chemistry
I am having trouble understanding what the concept is for writing these out. Write a balanced nuclear equation for the alpha decay of each of the following radioactive isotopes: curium-243, 22589Ac
Thursday, December 5, 2013 at 9:40am by ellie

Chemistry
radioactive sodium chloride is appropriate for diagnosing circulatory problems, but radioactive xenon is helpful in searching for lung problems. Explain why. I understand different elements are used for specific parts of the body but I don't understand this question. Thanks ...
Sunday, April 14, 2013 at 8:06pm by Sara

algebra
Scientists can determine the age of ancient objects by a method called radio carbon dating. The bombardment of the upper atmosphere by cosmic rays converts nitrogen to a radioactive isotope 14C of carbon with a half-life of about 5710 years. Vegetation absorbs carbon dioxide ...
Thursday, March 7, 2013 at 10:39pm by Emily

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

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
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

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

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

science - biology
A photosynthesis experiment uses Chlorella to track the route taken by 14C in photosynthesis. The 14C is provided from CO2 and no new sources of CO2 are available. After the experiment the scientist extracts all of the starch produced and analyses the Carbon present. She ...
Saturday, May 7, 2011 at 8:57am by jack

calculus
The rate at which an amount of a radioactive substance decays is modeled by the differential equation dA/dt = kA, where A is the mass in grams, t is the time in years, and k is a constant. Answer the following. a) If a 100-gram sample of the radioactive substance decays to 95 ...
Monday, March 19, 2012 at 12:43pm by ronnieday

biology
14 points Save A photosynthesis experiment uses Chlorella to track the route taken by 14C in photosynthesis. The 14C is provided from CO2 and no new sources of CO2 are available. After the experiment the scientist extracts all of the starch produced and analyses the Carbon ...
Saturday, May 7, 2011 at 9:01am by jack

Science
What can scientists learn from the rate at which radioactive elements decay? A. a rock's absolute age* B. the relative age of rock layers C. where one soil horizon ends and the next begins D. the difference between molds and casts. After six half-lives, what percentage of a ...
Tuesday, October 15, 2013 at 11:46am by Anonymous

Science
What can scientists learn from the rate at which radioactive elements decay? A. a rock's absolute age* B. the relative age of rock layers C. where one soil horizon ends and the next begins D. the difference between molds and casts. After six half-lives, what percentage of a ...
Wednesday, October 16, 2013 at 1:58am by Anonymous

Science
What can scientists learn from the rate at which radioactive elements decay? A. a rock's absolute age* B. the relative age of rock layers C. where one soil horizon ends and the next begins D. the difference between molds and casts. After six half-lives, what percentage of a ...
Wednesday, October 16, 2013 at 3:03pm by Anonymous

Science
Radioactive decay law N =N₀exp(-λt)= =N₀exp(-ln2t/T)= =20exp(-0.69318000/6000) = 2.5 g
Wednesday, December 5, 2012 at 4:21pm by Elena

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

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

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

Pages: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | Next>>

Search
Members