So ~ realizing the the fifty percent the quantity of 100mg would certainly be 50mg I put the 50 mg in my formula together the result. Thus,

$50 mg=100e^k30$

I divided both sides by 100:

$frac50100=frac100e^k30100$

$ln 0.5=ln e^k30$

$fracln 0.530=k$

k= -0.023

Answering part (b) should be easy after i find part (a)

(b) just how much of the sample remains after 100 years?

$P(100)=100e^-0.023cdot 100$

$10.025 mg=100e^-0.023cdot 100$

(c) After how long will just 1 mg remain?


calculus
re-superstructure
mention
follow
edited Aug 6 "15 at 13:15
sunny
inquiry Aug 6 "15 at 12:46

SunnySunny
1,07088 gold badges2020 silver badges3131 bronze title
$endgroup$
4
add a comment |

2 answer 2


active earliest Votes
2
$egingroup$
Your answer come a) is correct.Now it is really easy to deal with b) and also c) becuase you recognize the degeneration equation: $$P(t)=P_0 e^-0.023 t$$

so, for b) friend have:$$P(100)=100 e^-2.3 approx 10 mbox mg$$and because that c) you have to solve:$$1=100 e^-0.023 t$$ and you find:$$t=-dfracln0.010.023 approx 199.3 mbox years$$


re-superstructure
point out
monitor
edited Aug 6 "15 in ~ 13:32
answered Aug 6 "15 at 13:26
*

Emilio NovatiEmilio Novati
59.6k55 gold badges4141 silver badges101101 bronze title
$endgroup$
add a comment |
1
$egingroup$
In a, you require to provide the systems of $k$, yet are otherwise correct. Because that b, the is no rounded correctly and also not offered as an answer, but OK. For c, usage the same equation together you have, $1 mg=100 mg e^-0.23t$ and also solve for $t$


re-superstructure
mention
follow
answer Aug 6 "15 in ~ 13:19
*

Ross MillikanRoss Millikan
358k2626 yellow badges237237 silver badges425425 bronze badges
$endgroup$
2
add a comment |

your Answer


Thanks for contributing an answer to rememberingsomer.com Stack Exchange!

Please be certain to answer the question. Administer details and also share her research!

But avoid

Asking because that help, clarification, or responding to other answers.Making statements based upon opinion; earlier them increase with recommendations or an individual experience.

You are watching: The half life of cesium 137 is 30 years suppose we have a 100 mg sample

Use rememberingsomer.comJax to format equations. rememberingsomer.comJax reference.

To find out more, see our advice on writing good answers.

See more: What Does Clinical Correlation Recommended Mean, “Correlate Clinically”


Draft saved
Draft discarded

Sign increase or log in


sign up using Google
sign up making use of Facebook
authorize up utilizing Email and Password
submit

Post together a guest


name
email Required, yet never shown


Post together a guest


name
email

Required, yet never shown


short article Your answer Discard

By clicking “Post her Answer”, friend agree to our regards to service, privacy policy and also cookie plan


Not the price you're spring for? Browse various other questions tagged calculus or questioning your own question.


Upcoming events
Featured on Meta
related
1
Calc question on radioactive degeneration
0
Relative expansion Rate Question: A bacteria culture initially includes 100 cells and grows in ~ a price proportional come its size.
0
$M(t) = 50e^-0.02t$ because that A $N(t) = 75e^-0.01t+10$ because that B because that $t$ minute . Exactly how long until $M(t)=N(t)/2$?
0
Exponential Radioactive decay Problem
0
Is there a way to intuitively know this?
0
confuse text around Radioactive degeneration
1
determine rate of degeneration (calculus)
0
Why carry out we need to use the exponents for this degeneration probelem.
warm Network concerns more hot questions

concern feed
subscribe to RSS
inquiry feed To subscribe to this RSS feed, copy and paste this URL right into your RSS reader.


*

rememberingsomer.com
company
stack Exchange Network
site style / logo © 2021 stack Exchange Inc; user contributions license is granted under cc by-sa. Rev2021.11.12.40742


rememberingsomer.comematics ridge Exchange works best with JavaScript allowed
*

her privacy

By click “Accept all cookies”, you agree stack Exchange deserve to store cookies on your an equipment and disclose details in accordance v our Cookie Policy.