Nucleus Definition and 409 Threads

A (free) neutron has a lifetime of some 10 minutes or so, how come it is stable in a nucleus?

In Rutherford's scattering experiments, alpha particles (charge = +2e) were fired at a gold foil. Consider an alpha particle with an initial kinetic energy K heading directly for the nucleus of a gold atom (charge = +79e). The alpha particle will come to rest when all its initial kinetic energy...

Why does in QM the electron does not fall toward the nucleus? After all, the only force between nucleus and electron is attractive (- electron and + nucleus). Is the same reason that justifies the moon does not fall to the earth?

If a nucleus is in its first excited state, is its total rest energy then mc^2 + Eex1?

Homework Statement The low-lying levels of C-13 are ground state, \frac{1^-}{2}; 3,09 MeV, \frac{1^+}{2}; 3,68 MeV, \frac{3^-}{2}; 3,85 MeV, \frac{5^+}{2}. Interpret these four states according to the shell model. Homework Equations Negative parity --> \ell = odd; the valence nucleon must...

Can we have a nucleus containing neutrons alone? Thanks in advance.

I recently purchased a new book that reviews most historical models of the atomic nucleus: http://www.brownstationers.com/BookItem.aspx?item=9783540285694 This is the only book on this subject in the past 40+ years that gives positive review (well--any review actually) for the 1965 Linus...

Hey people, I have beeno wondering this for a while: If the nucleus of an atom is positively charged and the electrons are negatively charged, why don't the electrons stick to the nucleus like a magnet, why do they only have a certain distance between themselves. If the electrons are...

Homework Statement an alpha particle (charge=+2.0e) is sent at high speed toward a gold nuclues Charge= +79e. What is the electrical force acting on the alpha particle when it is 2.0 times 10^ -14m away from the gold nucleus Homework Equations The Attempt at a Solution its 91 N...

Hey all, I am currently revising for my Physics mock but i can't get my head around high energy electron scattering, and the proof this provides for the size of the nucleus. I have read from a variety of texts and some of the links on here but these have lead me to become even more...

this seems like a fairly simple problem, however I'm not sure if my calculation seems right... the question: The nucleus of a uranium atom has a diameter of 1.5 * 10 to the -14 and a mass of 4.0 * 10 to the -25. It then asks what the density of the nucleus is. I know that nucleus...

Can you tell me the answer to this question? Why would the scientific community resist the concept of a nucleus full of positive charges and what observations helped them explain this design. Thanks, v

Hi, this problem is killing me. What is the total charge of the radon nucleus? (The neutral radon atom has 86 electrons.) The units is in Coulombs so I figured since they were asking for the charge of just the nucleus then it would be 86 protons times -1.6x10^-19 C. But that didn't work...

Hi, this problem is killing me. What is the total charge of the radon nucleus? (The neutral radon atom has 86 electrons.) The units is in Coulombs so I figured since they were asking for the charge of just the nucleus then it would be 86 protons times -1.6x10^-19 C. But that didn't work...

# It is said that atoms of elements of high atomic mass are unstable. So they emit alpha, beta or gamma rays. Suppose an atom emits alpha rays. The binding energy of alpha particle is about 27 MeV(million electron volt). It is said that as a result of this emission, the binding energy per...

thanks hootenanny:wink: im not sure if my teacher had set this question wrongly or not? because I am finding it hard to answer. the question goes: TWO statement below are INCORRECT. which are these 2 statements? A.) the nucleus of an atom contains only neutrons and protons. B.)The...

Here is the question I am attempting to solve : A proton or neutron has a radius r of roughly 110-15 m, and a nucleus is a tightly packed collection of nucleons. Therefore the volume of the nucleus, (4/3)R3, is approximately equal to the volume of one nucleon, (4/3)r3, times the number N of...

To all: In some detail what makes the tritium isotope of hydrogen radiogenic? And since C12 and C13 are both stable what makes C14 unstable? Thanks Rieman Zeta

Ok, I have a question that's really irritating me. I am trying to explain why deuterium's nucleus has a spin of 1. By the addition of angular mometum of the individual nucleons (1 proton and 1 neutron) that make up the deuterium nucleus, there are three possible choices (from the triangle...

I am new to physics, so bear with as I don't know a lot yet. I was given this problem to figure out, but have been having a difficult time. A hydrogen atom has a diameter of approximately 1.06*10-10 m, as defined by the diameter of the spherical electron cloud around the nucleus. The...

Is it true that the probability of finding the electron (s-electron) increases if we go towards the nucleus? then what accounts for its stability from not being attracted by the nucleus n collapsing into it..its a basic question but i don't have an idea now! Is it just the concept of constant...

Since the nucleus of an atom is +charged and the electron is -charged, why doesn't at least one electron fall into the nucleus?

Can the nucleus of an atom have an overall “neutral charge” if there happens to be more neutrons in the nucleus than protons?

The nucleus of 214Po decays radioactively by emitting an alpha particle (mass 6.65*10^-27) with kinetic energy 1.23*10^-12 J, as measured in the laboratory reference frame. Assuming that the Po was initially at rest in this frame, find the magnitude of the recoil velocity of the nucleus that...

An alpha particle approaches a Au (gold) nucleus with atomic mass number 197 with a speed of 1.5*10^7 m/s. The alpha particle is then scattered 49 degrees from the horizontal at the slower speed of 1.47*10^7 m/s. In what direction does the Au nucleus recoil below the x-axis (the horizontal)...

QFT states that all forces are due to the exchange of virtual particles, I'm interested in photons and their role in the EM force. I was wondering what the maximum time allowed for existence of an exchange photon is when it's emmitted from a proton in the nucleus of an atom. I'm thinkin' that...

Some one please make me understand why electrons closer to the nucleus have less energy than the ones which are farther from it. Is it because they have more potential energy? Secondly, How do we know that protons exist as particles but not as a ball of positive charge. Thanks in advance for...

I've got this following question which I don't really get: What is the charge on the nucleus of each of the following? (assuming they are neutral) a) Mg b) Ne c) K^+ d) S^2- What I don't understand is the definition of "charge on the nucleus" I am assuming that only protons...

Consider a nucleus with N neutrons and Z protons. Can one justify it alternatively as a nucleus with N + Z protons and N electrons, the latter occupying orbitals either confined to the nucleus or following beta decay according to their electronic potential?

Assuming the electron is orbiting (semiclassical approach) the nucleus at the second allowed distance from it (2s, for example in H). When the electron decays (classical electrodynamics) it probably will do it in a kind of spiral trajectory. This trajectory implies acceleration and so, a...

As part of the ComPADRE Digital Library, the Nucleus is a resource for undergraduates in Physics and Astronomy. It has discussion forums, textbook reviews, online lessons by subjects, summer research openings, etc. Currently, they are highlighting the translation of Einstein's Special...

A 232 Th (thorium) nucleus at rest decays to a 228 Ra (radon) nucleus with the emission of an alpha particle. The total kinetic energy of the decay fragments is 6.54 x 10^-3 J. An alpha particle has 1.76% of the mass of a 228 Ra nucleus. a) Calculate the kinetic energy of the recoiling 228 Ra...

I have my doubt,solution and question in the attachment that followed.Thanks for anybody that spend some time on this question.

Hey guys, I know this is basic nuclear physics but I've forgotten how to do it. Given the atomic mass of Oxygen 16 (8p 8n), Oxygen 15(7n 8p) and Nitrogen 15(8n 7p), having found the average energy binding energy per nucleon (i think i have it right) find how much energy is required to remove...

Do the electrons spin around the nuclues? If so, do we know the value?

Here I have a problem: A 232/92 Uranium nucleus emits an alpha particle with kinetic energy=5.32MeV. What is the final nucleus and what is the approximate mass(in units) of the final atom. I can write the equation for the reaction, this will give 4/2 He and 228/90 Th. If the alpha particle...

Is the spin of an atom come from (or based on) the Nucleus (i.e. net of Neutrons and Protons)? With the spin of the Electrons not really noticed or counted though a sense of being ‘lost’ or masked by being in an orbital?

In a recent discussion in this thread I wrote: Using classical mechanics and electomagnetism, work out the speed that an electron would have to have in order to orbit a hydrogen nucleus at a distance of 10^-12 m: F_c = \frac{m_ev^2}{r} = \frac{kq_e^2}{r^2} v = \sqrt{\frac{kq_e^2}{mr}}...

Apart from inertia and a nucleus' "gravity" (I invisage it's like the planets revolving around the sun), are there any other factors that keep the electrons from being attracted to the protons and crushing into the nucleus?

Consider the ground state of the hydrogen atom. Estimate the correction \frac{\Delta E}{E_1s} caused by the finite size of the nucleus. Assume that it is a unifromly charged shell with radius b and the potential inside is given by \frac{-e^2}{4\pi \epsilon b} Calculate the first order...

I'm not sure if these are very clear questions, but here goes: 1. If a fairly large nucleus is set spinning, then it should generate a small magnetic dipole, right? I'm wondering, how would you calculate it's magnetic moment, using the properties of that particular nuclide (e.g. mass, charge...

For a ground state Hydrogen atomic system (1 electron and 1 proton - not molecular di-hydrogen), what energies are being exerted by the proton to hold that electron? Does TE = KE + PE apply?

What speed do subatomic particles travel around the nucleus? Do the speeds vary with different paricles, IE Electron, Proton, Neutron? Are the speeds differnet with its idenical positron? I do know that electrons and protons travel around the nuclueus at differnt speeds, this we call "heat"...

Can anyone explain to me why gravity would not be a significant force on the 'surface' of a proton or neutron? A quick calculation shows that the acceleration of a neutron toward another neutron or a proton separated by less than the radius of a neutron, is very large (compared to the radius of...

I read somewhere that one of the explanations for an electron not spiraling into the nucleus is due to the uncertainty principle. If an electron falls into the nucleus both its position and velocity will be certain. How is that possible? Does the nucleus have both certainty in position and...

OK having a slight problem finding the mass of the unknown nucleus. Any help rearranging to find this using Newton's Gravitational law. A hydrogen nucleus and a nucleus of an ‘unknown’ atom are stationary, 5.0 x 10 ^-10 m apart. The mass of the hydrogen nucleus is mh = 1.7 x 10 - 27kg and...

What holds the nucleus together?

Is it known what the salt conditions are like in the nucleus? For instance, in the cytoplasm [KCl]=100mM [NaCl]=10mM.. would this be very different in the nucleus? Which salts would be important in influencing protein/protein or protein/DNA interactions?

"completely stable nucleus" question The nucleus of a helium isotope contains 2 protons. I have just worked out the magnitudes of the electrostatic force and the gravitational attraction between the 2 protons. The question now reads "the nucleus is completely stable. Considering the...

If oppositely charged particles attract, then why do electrons orbit the nucleus and not stick to it as the nucleus is positively charged and the electrons being negatively charged?