Radioactive Definition and 391 Threads

I read from various sources that Non-baryonic matter (primarily WIMPs) is the best candidate to explain a number of cosmological phenomena. Why would the phenomenon of radioactive decay not be attributed to these abundant (over 1/4 of the mass-energy of the universe) particles? I'm not trying to...

1. Create and solve differential equations for the number of different amounts of isotopes, which change through time in the decay chain X -> Y -> Z, where X and Y are radioactive atoms, and Z is a stable atom. 2. Make a mathematical analysis of how the different amounts of isotopes from 1 mg...

Homework Statement Homework EquationsThe Attempt at a Solution Is there anyway to choose the correct option without solving it? ## \lambda = \frac { 0.693 } { t_{\frac 1 2}} ## [/B] ## N = N_0 e^{- 0.693 {\frac { t } { t_{\frac 1 2 }}}} ## ## N = 10.24 e^{- \frac { 0.693 * 38 } {...

Hello, I am a Mechanical Engineering student but I am a TA for an electricity and magnetism course, and I had a student ask a question that's a little bit outside my understanding. The question was related to the equation for a radiating electric field from an accelerating charged particle...

Homework Statement Two species of radioactive atoms are mixed in equal numbers. The disintegration constant of first species is ##\lambda## and that of second species is ##\frac \lambda {3}##. After a long time, the mixture will behave as a species with mean life ________. Homework Equations...

Hi, thanks to a different thread/question on this forum I've come to appreciate time dilation ..somewhat. And from that I wondered if, given the range of locally measured times aboard any and all particles in the universe, given their different trajectories and histories since the big bang...

Homework Statement Analyzing a rock sample, it is found that it contains 1.58 mg of 238U and 0.342 mg of 206Pb, which is the stable final product of the disintegration of 238U. Assume that all 206Pb found comes from the disintegration of 238U originally contained in sample. How old is this...

Alright, a very simple question here. I am reading about nuclear decay of Carbon 14 into Nitrogen 14. I understand how one electron is released and subsequently one neutron turns into a proton, but I am curious about how many electrons are left with the Nitrogen atom. I want to believe five, as...

Last year in a Intro to Radiation Oncology lecture I was sitting in on, a physics professor at my school said that all a terrorist (or otherwise bad guy) would need to do to kill or at least harm a bunch of people is take a small amount of radioactive material and hide it somewhere in a desk. He...

I viewed the answers to the non repliable post https://www.physicsforums.com/threads/is-radioactive-decay-reversible-in-time.673735/, but I have doubts. In particular, the last claim by nugatory: "the overall decay of the sample is as irreversible as the transfer of heat from a hotter body to a...

Homework Statement Archeologists removed some charcoal from a Native American campfire, burned it in O2, and bubbled the CO2 formed into Ca(OH)2 solution (limewater). The CaCO3 that precipitated was filtered and dried. If 4.58 g of the CaCO3 had a radioactivity of 3.2 d/min, how long ago was...

Hello! I'm a high school science teacher who was recently switched to teaching physics for the first time mid-year. I remember doing an electroplating demonstration in my gradeschool days for a science fair. It was fascinating and now I want to give my students a chance to do some hands-on...

Small radioactive sources are often used for laboratory experiments. They are enclosed in a metal container with a small window. A gamma source might be covered by a stainless steel window. What would you expect the window of an alpha source to be like, and why? (I know the answer has to do with...

Hello All, Is it possible to analyze signals/photons/pulses from a 57Co source (strength 2 microCi) using a ADC (multihit readout) with 5 GS/sec? Just to look at pulse height spectrum..also I am interested to make a coincidence counting between 122 adn 14.4 keV levels! I heared that these ADCs...

I'm stuck on this idea. How are initial radioactive isotope quantities assumed in radiometric dating? There are current abundances for all isotopes, but wouldn't these abundances have been different in the past (much higher)? I honestly can't grasp how radioactive isotopes with short half lives...

If I was to throw together I variety of radioactive materials into a pot, what would be the interaction between the different materials? If I threw together Barium and Polonium, what would happen? What if I added Cesium, Europium, and Strontium to the mix? What about throwing in Uranium? Will...

How would one go about determining the amount of heat generated by the decay of a radioactive particle, such as Cesium 137, Polonium 210, or Strontium 90? How would you determine how much of the radioactive material would be needed to heat, say, a cup of water to a certain temperature, taking...

I was researching on radioactive elements and found out that polonium is the most radioactive element and the most radioactive isotope of polonium (out of 33!) is polonium 210. So I was wondering why it isn't used in nuclear plants and bombs. I know that if a slow neutron was to hit uranium 235...

Is there a way or process to neutralize the radioactive properties of a material (i.e. Make a radioactive substance stop ionizing it's surroundings?) Alternatively, since the gamma radiation penetrates through materials the most, is there a way of "slowing down" the frequency (lowering the...

what conditions must occur randomly to allow a radioactive nucleus to decay spontaneously?

Homework Statement The potassium isotope 4219K has a half-life of 12 hr, and disintegrates with the emission of a γ-ray to form the calcium isotope 4220Ca. What other radiation besides γ-rays must be emitted? How many electrons, protons, and neutrons are there in an atom of the calcium isotope...

When reading about radioactive decay, I see two types of decay constants: λ and "k". From what I have interpreted, k = ln (.5) / half-life whereas λ = ln (2) / half-life. Have I defined these correctly? If this is so, the difference between the two is slight. When putting these into equations...

Why do radioactive materials decay in half-lifes exponential decay and not over mean time, i.e. like a Bell Curve

Hi, ok another strange question: how does this work: <link to video deleted> or what exactly is the science behind it? I saw it on BBC and they told something like "the low density of the gas is a result of the radioactive decay" i don´t get it. maybe someone could explain.

Radioactive decay is known to be a pure quantum effect, the particle from the nucleus is in a superposition until we measure it (according to collapse interpretations). In the Sch. cat experiment the radioactive particle gets entangled with a macroscopic object (Geiger counter) and so the...

Hi all! I have a certain quantity of a radioactive material (e.g. 1 kg) in the open space. How can I calculate the temperature of this material as a function of time? If it is useful, we can consider a beta decay material. Thanks a lot.

Homework Statement About a day after the Chernobyl disaster the radioactive fallout landed in Sweden. The relative activity of ##^{133}I (t_{1/2} = 20.8h )## and ##^{131}I (t_{1/2} = 8.02 d)## were measured at 28/4 17:00 at ##270## mBq and ##1000## mBq respectively. Determine the time of the...

Hello, I wish to ask, if a kind of nuclear attack would happen, what radiation would it be, how far and for how long? How can we know how the radioation amount would change with time? Many thanks!

You can model the probability for radioactive decay as a Poisson distribution. This is the probability for radioactive decay within a specific time interval. (I probably got some of it wrong here). P(k,μ)=λ^k⋅exp(-μ)/k! Is there a way to use this formula to derive the other formula for...

Consider an ensemble of identically prepared pencils balanced on its tip. If a pencil is precisely vertical, ##x=0##, and precisely at rest, ##p=0##, then it will never fall. But some pencils in the ensemble would fall, because according to the uncertainty principle, the standard deviation...

Is the rate of radioactive decay fixed or does the environment have any impact eg would the rate of decay be the same in a low or very high gravitational field (in both cases measured from the viewpoint of the radioactive material)?

It seems odd to me that there would be a radioactive atom so far up the periodic table. What is it about this atom's atomic nucleus that makes it so unstable?

Basic high-school homework. I mostly just want feedback on my answers and advice :) The experiment was to: Drop pins into a box. Pick out the one's upside down and count them and these are the ones that underwent decay. Get the ones that weren't upside down and throw them into the box again...

Really wishing I had paid more attention in high school. I assumed that reactive meant that the element either needed to gain or lose electrons causing it to "want" to grab onto another or be grabbed. Sodium being an example. If I am correct with that part, this next part is where I am picking...

Hello, Are there any anthropologists, archaeologists, or geologists around on this board for help? I am trying to teach myself about radioactive decay via beta emission whereby a neutron spontaneously transmutes into a proton, releasing an electron. But, I do not understand the practical side...

Hi everyone this is my first time posting here, First of all, excuse my english because here in Mtl we speak French mostly. My team and I are working on an university project in Montreal (Qc) Canada (Polytechnique) regarding the recycling of radioactive material waste. We are working on the...

Homework Statement The masses of the following atoms are: 238 U → 238.050786(2) 234 Th→ 234.043598(5) 4 He → 4.002603 a) Calculate the energy available in the decay of 238U. b) Calculate the decay rate of 238U 238U half time = 4.468*10^9yrs c) If a block of uranium produces 1mW of power...

Homework Statement A radioactive material decays by simultaneous emission of two particles with respective half lives 1620 and 810 years. The time, in years, after which one-fourth of the material remains is: Homework EquationsThe Attempt at a Solution I'm confused whether the half lives...

Homework Statement Two isotopes N1, N2. You are given the value of the proportions N1(t1)/N2(t1) and N1(t2)/N2(t2). From this calculate Δt. Homework Equations dN/dt = -λN The Attempt at a Solution Solve dN1/N = -λdt and dN2/N = -λdt obtain: N1(t2) = N1(t1)exp(-λ1(t2-t1)) (1) and N2(t2) =...

When electrons of high energy fall on metal X rays are produced.What about the metals having large atomic number and showing natural radio activity?Will there be a collision between the electrons and alpha and beta particle? I can not understand this. So please help me.

Among the radioactive products emitted in the 1986 Chernobyl reactor accident were 131I ( t1/2 = 8.0 d) and 137Cs (t1/2 = 30 y). There are about five times as many 137Cs atoms as 131I atoms produced in fission. (a) Which isotope contributes the greater activity to the radiation cloud? Assume the...

Homework Statement Charred wood remains were found in Conimbriga, probably with Roman origin. When measured at 14C activity in these remnants, it afforded 10.8 disintegrations per second per gram. The half-processing 14C is 5730 ± 30 years and the activity of this isotope in the atmosphere and...

I was wondering if anyone could give me some insight as to what I found at my work the other day. We have old chemicals (some REALLY old) that turn up in random cabinets from time to time, and this time I was a bottle with a mostly-decayed label where the only thing that could be read was...

Hi guys, in my plot I have an unstable isotope of an alien element and I was wondering wouldn't it be nice if most of the particles generated from the decaying are entangled, how do you think, does it sound silly and totally impossible? If it is a good idea, then how such a property can be used...

Homework Statement If a radioactive sample of 59Fe (t1/2= 44.496 d) has an activity of 1000 disintegrations per minute, what weight of 59Fe is present? Homework Equations

Homework Statement Are the number of electrons on both sides of the radioactive decay balanced? Homework Equations For example, consider an alpha decay. ZPA → Z-2DA-4 + 2He4 For P, Number of Neutrons = A - Z Number of Protons = Z Number of Electrons = Z For D, Number of Neutrons = [A - 4] - [Z...

Also, How do we know the radioactive decay is constant? I know that carbon dating cannot be 100% accurate because the rate of production fluctuates based on cosmic rays hitting our upper atmosphere. Why isn't this true with Earth metal isotopes? Is time truly constant? It seems like a lot...

Hi Guys Is there a simple test by which one could determine the type of decay a radioactive specimen is undergoing? Thanks sonip

what causes radioactive decay i mean i know throw decay could turn unstable to stable atom. But what cause it unstable?

Homework Statement If a radioactive isotope ends with 55.5 g, and has a half-life of 2.5 days, how much was there 8.3 days ago? Homework Equations mf=mi(1/2^t/h) The Attempt at a Solution the answer i got was 554 g, is it correct?