Problem 403. Einsteinium-253 decay

Created by Bruce Raine

Solve Later

{"relationships":[{"relationshipType":"http://schemas.mathworks.com/matlab/code/2013/relationships/document","relationshipId":"rId1","target":"/matlab/document.xml"},{"relationshipType":"http://schemas.mathworks.com/matlab/code/2013/relationships/output","relationshipId":"rId2","target":"/matlab/output.xml"}],"parts":[{"partUri":"/matlab/document.xml","relationship":[],"contentType":"application/vnd.mathworks.matlab.code.document+xml","content":"<?xml version=\"1.0\" encoding=\"UTF-8\"?><w:document xmlns:w=\"http://schemas.openxmlformats.org/wordprocessingml/2006/main\"><w:body><w:p><w:pPr><w:pStyle w:val=\"text\"/></w:pPr><w:r><w:t>Radioactive Einsteinium-253 has a half-life of 1,768,608 seconds. Given 1000mg of Einsteinium-253 at t=0 days, how much is left after 50 days?</w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"text\"/><w:jc w:val=\"left\"/></w:pPr><w:r><w:t>EX: >> decay(50)</w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"text\"/><w:jc w:val=\"left\"/></w:pPr><w:r><w:t>184</w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"text\"/><w:jc w:val=\"left\"/></w:pPr><w:r><w:t>HINT: find k, then decay(50)</w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"text\"/><w:jc w:val=\"left\"/></w:pPr><w:r><w:t>Use: decay(t)=10^3*e^(k*t)</w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"text\"/><w:jc w:val=\"left\"/></w:pPr><w:r><w:t>NB: make sure you round your answer up to the next highest integer.</w:t></w:r></w:p></w:body></w:document>"},{"partUri":"/matlab/output.xml","contentType":"text/xml","content":"<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"no\" ?><embeddedOutputs><metaData><evaluationState>manual</evaluationState><layoutState>code</layoutState><outputStatus>ready</outputStatus></metaData><outputArray type=\"array\"/><regionArray type=\"array\"/></embeddedOutputs>"}]}

Solve

Solution Stats

233 Solutions
112 Solvers

Last Solution submitted on Aug 15, 2020

Last 200 Solutions

Problem Comments

5 Comments

5 Comments

Show 2 older comments

Alfonso Nieto-Castanon on 25 Feb 2012

guess you mean minutes instead of seconds?

Bruce Raine on 25 Feb 2012

Hi, no I do mean seconds if you are referring to the constant, 29,476.8

Bruce Raine on 25 Feb 2012

I have readjusted it now so it is the correct value.

Rick Rosson on 25 Feb 2012

I believe you are always rounding up to the next highest integer rather than rounding to the nearest integer. In other words, you are using the ceil() function, not the round() function.

Bruce Raine on 25 Feb 2012

Hi Rick, yes you are quite right. I have made the correction as above. Thanks for your valuable input.

Solution Comments

Solution 51323

2 Comments

2 Comments

@bmtran (Bryant Tran) on 25 Feb 2012

I believe your second test case is incorrectly rounding.

Bruce Raine on 25 Feb 2012

Yes, you were right with my earlier incorrect "note well" remark but now with corrected remark in place this test is valid. Sorry if it has put you off a bit. I guess other issues may come to light as well but I hope not.

Problem Recent Solvers112

Problem Tags

half-life isotope natural log radioactive decay

Problem 403. Einsteinium-253 decay

Solution Stats

Last 200 Solutions

Problem Comments

Solution Comments

Problem Recent Solvers112

Suggested Problems

More from this Author16

Problem Tags

Problem 403. Einsteinium-253 decay

Solution Stats

Last 200 Solutions

Problem Comments

Solution Comments

Problem Recent Solvers112

Suggested Problems

More from this Author16

Problem Tags

Players