Half life Definition and 125 Threads

Homework Statement http://img5.imageshack.us/img5/8553/halflifei.th.jpg I need to find the half life time of a capacitor and the equation is above.. I know what C is but I don't know R.. is there a way to calculate R in this case? Homework Equations The Attempt at a Solution

Homework Statement If I have a circuit in which the capacitor is the large disk device and for each value of separation=d, calculate the half-life of exponential decay? Homework Equations The Attempt at a Solution What is the formula to do this?

I have completed an experiment to measure the decay rate of an isotope, and I am trying to estimate uncertainties. The half life is 40 seconds, with decays counted over a 15 second period (with many of these 10 second periods for a total of 6 minutes of recordings) However in more detailed...

Homework Statement A radioactive needle contains 222 Rn (t1/2=3.83 d) in secular equilibrium with 226 Ra(t1/2=1600 a). How long does is it required for 222 Rn to decay to half of its original activity?Homework Equations A(t) = -\frac{dN(t)}{dt} = \lambda N(t) The Attempt at a Solution...

Hello all, Below I have a few questions regarding calculating the half life of muons. We measured how many muons were recorded at the top of a mountain, then measured how many muons were recorded at the bottom. Using this data, we calculated the half life of moving muons. Thanks for the...

Homework Statement A radioactive material has a half life of 1550 years. Find the time during which a given amount of this material is reduced to one forth. I am really not sure how to do this since we have not covered it in class yet. But, a formula that I have found involves find the...

how do you delete posts? i was going to post a question and i accidentally posted it how do i delete this error?

Homework Statement An extra solar planet is discovered that is 500 light-years away. It is found through spectroscopic analysis that the abundance of potassium - 40 to potassium - 39 on the planet is 99.9%. Assuming that the planet was created with equal amounts of the two potassium isotopes...

Is there any theory that predicts the halflife of a radioisotope given the number of neutrons and protons in the element? For example, given X protons and Y neutrons, is there anything other than empirical data to predict when half of a given sample will decay? I know there are isalnds of...

If the rate of an isotope in 18 days has dropped by one eight of its initial value. what is the half life of the isotope? My answer In 18 days the rate has dropped by 1/8 so therefore the half life is 4/8 which is 18*4 = 72days

Homework Statement Thorium-234 has a half life of 24 days. If you begin with a 280 kg sample, in how many days will you have 17.5 kg of Thorium left? Homework Equations DONT KNOW EQUATIONS The Attempt at a Solution DONT KNOW HOW TO START. I AM CONFUSED

Homework Statement A certain first-order reaction has a rate constant of 6.70×10−3 . How long will it take for the reactant concentration to drop to 1/8 of its initial value? Homework Equations half life =0.693/k The Attempt at a Solution half life = 0.693/(6.70×10−3) = 103.43...

Assume you have a med with a 72 hour half life, but that is dosed daily. How much elimination occurs each day of the drug, and what is the steady state dose compared to the daily dose? Is it just a linear decrease, so you take 50/72= 0.667, and multiply 0.667x24= 16 which means everyday 16%...

Homework Statement Homework Equations HalfLife = 1 / k*[A]i where k is the rate constant and [A]i is the initial concentration of a reactant A. The Attempt at a Solution I don't have enough information to attempt this problem. I don't know what to do with the partial pressure...

A sample of tritium 3 decayed to 94.5% of its original amount after a year. (a) What is the half-life of tritium-3? (b) How long would it take the sample to decay to 20% of its original amount? The only equations given in my book are dm/dt = km and m(t) =...

In my assay of 50uL of 125-I-insulin I have 20,000 cpm at the expiry date. The half life of 125-I-Insulin is 60 days. So how can I calculate how many counts a 50uL sample of 125-I-labelled insulin would contained at 4 months past the expiry date? cheers

Hello All, I would like to know how would I go about determining the half life of an isotope when this infoormation is give to me: Time (hr) Mass Remaining of the Isotope (g) 0.0 40.00 3.0 20.00 6.0 10.00 9.0 5.00 12.0 2.50 15.0...

Its seems to me that, unlike physicians, who have ER, Scrubs, etc., lawyers, who have, Law and Order, Boston Legal, etc., and, cops, who have, CSI, Cops, etc., Physicists don't get much of a spotlight in the area of public entertainment. The one exception I can find are these two computer...

Iodine-131 is used in treatment of thyroid disorder. This isotope has a half life of 8.04 days, what percentage of an initial sample is left after 30 days? having done, the initial calculations by taking 30 divided by 8.04 to find how many hl will have passed i take the number and i take the...

hey can someone help me out with this question...I have an test 2mr on this time and don't have any more time to waste. So can someone please show me how to do it...so I can study of it...thanks in advance Scientist are able to determine the age of very old, naturally occurring items...

howdy, how can one determine molar mass when the half life and dacay rate (d/min) and mass of matter are known? I am really puzzled. thanks for the help.

Half Life Problem help PLEASE PLEASE The plutonium isotope Pu-239 is a radioactive material. The half-life of plutonium isotope Pu-239 is 24360 years. If 10 grams of Plutonium were released in the nuclear accident, how long will it take for the 10 gram to decay to 1 gram? Round off your...

I've heard it is possible to play with Half Life making some tricks. But all of them requires the presence of the console window. I pulse the key "º" during the game, but no console window is showed. I have seen some people make a shortcut with a direct access to...

Hi! I'd like to make some half-life measurements on water based foams. I have only simple instruments for it. Can anybody help me? I don't know the exact method that how to make this measurement correctly. And I also need the mathematical apparatus for it. I've found an article where the...

[SOLVED] Half Life I can't get the answer to this question. If Hydrogen 3 ( 3H ) ( 1 ) has a half life of 12.5a, how many years have passed when only 1/64 of its original mass remains?