Nucleus Definition and 423 Threads

  1. B

    Atomic Nucleus: How Does It Get Energy?

    How does the nucleas of an atom get energy?
  2. J

    Calculating avg distance from nucleus

    Homework Statement Calculate the avg. distance from the Hydrogen nucleus for an electron in 2p. Homework Equations <r> = int[r^3 |R|^2]dr from 0->infinity For Hydrogen 2p, R = (1/a)^3/2 (1/(2*sqrt(sigma))*sigma*exp(-sigma/2) where sigma = r/a The Attempt at a Solution I get 1/4a^4 (24...
  3. matt_crouch

    How to calculate the density of an iron nucleus

    Homework Statement An iron nucleus has a radius of 5.4x10^-15 and a mass of 9.3x10^-26 what is its mass per unit volume in kg/m^3 Homework Equations Area of a sphere = 4/3(pi)r^3 Density= M/V The Attempt at a Solution i basically plugged everything into the equations so...
  4. G

    Bonding force of an optical electron and the nucleus of ion Cr3+

    Does anybody know how to find bonding force of an optical electron and the nucleus of ion Cr3+ (in pink ruby during normal and excited states (excitement of light))? And also how to find the magnetic moment of the same electron during EPR (during excitement by a radiowave)? Condition of the...
  5. B

    Electric field of a charged nucleus (sphere) Gauss Law

    ok guys.. this question is regarding a spherical nucleus with radius R related to Gauss's Law... so where the electric field given as the following: E(r) = Q/4*pi*epsilon-nought(r^2+R^2) 1. the questions asks "why this model/behaviour for r>>R might be "reasonable" 2. what q(r) is needed...
  6. J

    Repartition of n's and p's in nucleus

    How do protons and neutrons behave in nucleus? Is they just sit where? Or move some how? or maybe jei form some form constant to that nucleus, like in solid state materials atoms forms crystal grating( I do not know how to call it in English). Maybe protons is more found in outside nucleus...
  7. D

    Why do electrons have more kinetic energy when closer to the nucleus?

    Also similarly, why do electrons have less potential energy when closer to the nucleus? Please can someone help me and explain in laymen's terms? I don't understand it. I know when electrons are separated by large distances, they are less likely to interact with the positive charge of the...
  8. T

    Does Time Affect Nucleus and Electron Interactions?

    I was wondering the following: Does time effect the nucleus and Electron differently? Since Electrons travel at extreme speeds while the nucleus is almost static? How does time effect the area between the two?
  9. C

    Why electrons can't remain in the nucleus

    Homework Statement Estimate the momentum of an electron confined to an atomic nucleus of radius a, and deduce a formula for its speed. By comparing the speed to the escape velocity explain why electrons cannot remain in the nucleus. Homework Equations Uncertainty principle The...
  10. V

    Liquid Drop Model of the Nucleus

    Looking at the liquid drop model of the nucleus and the semi-empirical formula for the atomic mass of the nucleus. I understand the formula but I'm trying to figure out why some nuclei are unstable against both beta- and beta+ decay. Any ideas? I assume it's something to do with the...
  11. V

    Fermi Energy of 40P 50N Nucleus Sphere

    Homework Statement I am wondering about something: Calculate the Fermi energy for the neutrons confined to a nucleus with 40 protons and 50 neutrons which roughly forms a sphere of radius 4.6 10^(-15) m. Homework Equations the formula of the fermi Energy is EF=...
  12. V

    Calculating Fermi Energy for Neutrons Confined to a Nucleus

    I am wondering about something: Calculate the Fermi energy for the neutrons confined to a nucleus with 40 protons and 50 neutrons which roughly forms a sphere of radius 4.6 10^(-15) m. the formula of the fermi Energy is EF= ((h-bar)^2*(3*pi^2*n)^(2/3))/2m m:mass of electron, n = number...
  13. T

    Why doesn't the electron fall into the nucleus?

    why doesn't the electron fall into the nucleus!? yes I know this question must have been asked before right? tried looking for it on here but I couldn't find it. the only answer I have gotten to this was just that particles are quantized... yes yes, fine... but WHY? for instance, why does an...
  14. E

    Given properties of nucleus, find its atomic number, mass, and element symbol.

    Homework Statement An unknown nucleus contains 71 neutrons and has twice the volume of the nickel http://www.webassign.net/www32/symImages/f/1/3dca243bf11d1adbce4ca198d1973f.gif nucleus. Identify the unknown nucleus. Homework Equations r = (1.2X10^-15)(A^(1/3)) V= (4/3)(pi)(r)^3...
  15. W

    Estimating Alpha Particle Speed & Kinetic Energy in a Heavy Nucleus

    Homework Statement Use the uncertainty principle to estimate the minimum speed and kinetic energy of an alpha particle confined to the interior of a heavy nucleus. Homework Equations delta_p*delta_r = h_bar/2 for minimum momentum p = mv for non-relativistic particle, the alpha...
  16. P

    What Causes the Mass Defect in a 15N Nucleus?

    What is the mass defect of the 15N nucleus? My attempt: 15-7=8 7(1.008665)+8(1.0078225)-14.003074 =1.120161 the answer needs to be in u so i don't know if this makes a difference or not but for some reason it is not working
  17. K

    Californium-242 nucleus 242/98 Cf decays via alpha decay

    Hey I'm new to this forum, just want to say hi! I'm not sure if this is the rite place to put this but sry if i posted in the wrong section >.< I'm actually working on an assignment in my natural science course and I'm stuck on this question cause I'm not sure how to use the variables in the...
  18. D

    Is a Hydrogen Nucleus the Same as a Proton?

    I thought that the hydrogen nucleus is just a single proton. So why does this page mention "electorns, protons, hydrogen nuclii", etc? http://blogs.discovermagazine.com/badastronomy/2009/04/07/hot-light-from-a-cold-comet/
  19. D

    How do scientists know the structure of the nucleus

    was it something that was figured out solely through atom smashers?
  20. R

    Kinetic energy of a recoiling nucleus

    A Fe nucleus at rest emits a 14.0-keV photon. Use conservation of energy and momentum to deduce the kinetic energy of the recoiling nucleus in electron volts. (Use Mc2 = 8.60E-9 J for the final state of the Fe nucleus.) what I have so far is... E = pc because E >> photon rest energy , which =...
  21. I

    How do you find the direction and magnitude from a nucleus?

    Homework Statement The nucleus of an atom has a charge of 65 protons. (a) What are the direction and magnitude of the electric field at 4.9 x 10^-10 m from the nucleus? (b) What are the direction and magnitude of the force exerted on an electron located at this distance? Homework...
  22. E

    How do you estimate the mass of a nucleus?

    Homework Statement Estimate the mass of a nucleus with a radius of 2.80 * 10^-15m. Homework Equations I do not know if there is an 'equation' for this. The Attempt at a Solution The answer is 2.11*10^-26.. but I don't even know how to approach this question.
  23. P

    Alpha Particle shot at Nucleus Energy

    Homework Statement What energy alpha particle would be needed to just reach the surface of an Al nucleus if its radius is 4fm? *This problem is found in a section dealing with Rutherford's gold foil scattering experiment, so take it in that context. Homework Equations F=(kqQ)/r2 The Attempt...
  24. G

    The Nucleus or Nucleon or Neutron Bomb

    Well I was talking to my physics teacher because were currently studying nuclear physics. And he likes tellign stories to make his examples more straight foreward. And I asked the question what types of radiations are in nucleaar bombs. Gama, Beta or alpha. He answered me with those three types...
  25. X

    Why spin 1/2 nucleus has no quadrupole?

    Hi: I am confused that we talk in general about only nuclear spin larger than 1/2 which has electric quadrupole. For spin half, there is no quadrupole because of its spherical shape. Anyone can comment on why they are sphere? what is physical significance behind? I read some research articles...
  26. P

    Elastic collisions between proton and helium nucleus

    Homework Statement In an elastic collision between a proton and a helium nucleus at rest, the proton was scattered through an angle of 45 degrees. What proportion of its initial energy did it lose? what was the recoil angle of the helium nucleus? Homework Equations...
  27. B

    Electron Motion Near Nucleus: Calculating Period and Velocity

    Homework Statement What is the magnitude of the electric field at a distance of 5.00 ×10−10 m from a radon nucleus? =4.95×1011 N/C What is the magnitude of the force on an electron at that distance? =7.94×10-8 N Now here is where I am getting stuck.. Treating the electron classically...
  28. N

    Can the Pauli Exclusion Principle explain the quantization of the nucleus?

    My professor mentioned that the pauli exclusion principle applies to the nucleus. How exactly is the nucleus quantized (the protons and neutrons), and how do the quantization rules apply to it (such as pauli's, hunds, and so on). Also, is this the reason why we don't observed multiple neutrons...
  29. A

    Can a stable nucleus ever spontaneously become (temporarily) unstable?

    Hi folks, I have what might be a naive question about the decay of unstable nuclei. I've recently been reading about various decay processes (e.g. beta decay, electron capture etc.). Specifically, I'm wondering if it is ever possible for a stable nucleus (say, carbon-12 or any other...
  30. C

    Electron-Proton Collisions: Understanding the Quantum Dynamics

    I think this is where I need to be thinking at a quantum level and not a classical level but i keep thinking if an electron travels at the right heading at an atom it would just crash into the nucleus and since opposites attract they would bond and have a nucleus with an electron sticking to it...
  31. V

    The force, which attracts e to nucleus

    Everybody knows that the nucleus attracts the electron by the Coulomb discovered electric attraction force: F = k / r2, which means the further is the electron from the nucleus r, the weaker is the attraction force. On the other hand, those familiar with the classic radio wave theory know...
  32. D

    What keeps protons together in the nucleus?

    what causes the protons inside the atoms nucleus to stay together(next to one another), positive repels positive, therefore they should repel each other,
  33. A

    Calculating Decay Rates of a Nucleus with 2 Channels

    Homework Statement A nucleus decays into two channels with probabilities 0.62 and 0.38, respectively. Its lifeime is 20 hours. What are the decay rates into each of these channels? Homework Equations If there is only one channel of decay, the decay can be described by the formula...
  34. N

    How Does an Electron Behave Near a Nucleus?

    I am sure it is easy to do, but I just can't seem to figure the question out. It is 4 parts and I got the first 2 parts. If someone can give me the steps with the numbers (already handed in assignment, and got it incorrect), that would be much appreciated. 1. What is the magnitude of the...
  35. P

    Mitochondria: Nucleus or No Nucleus?

    Do mitochondria have like tiny nucleus? and if not how do they control their DNA replication and translation... thnx
  36. D

    Is there any way to find the distance between a nucleus and its electrons?

    Is there any way to find the distance between a nucleus and its electrons? If possible, how can you figure out the distance between the nucleus and the electrons of an atom? Specifically, a carbon atom?
  37. M

    Calculating Carbon Atom Nucleus Charge - Marco

    hi this is probably basic physics but how do u work out specific charge of say the nucleus of a carbon atom? thanks Marco
  38. H

    Elastic Collision of a gold nucleus

    Homework Statement A positively charged alpha particle is fired, in a direct line, at a positively charged gold nucleus: o--> O o: alpha, O: golden nucleus. Because of their mutual repulsion, the alpha particle does not actually hit the nuleus: it comes to rest, for a...
  39. A

    How Has Our Understanding of the Atom Changed Since Thomson's Model?

    Question: In 1997 we celebrated the centenary of JJ Thomson’s discovery of the electron. Thomson pictured the atom as being like a currant bun, with electron ‘currants’ embedded in a positively charged ‘bun’. Give a short account of three ways in which our model of matter on a subatomic scale...
  40. A

    Finding Magnitude of Force of a Nucleus

    Homework Statement A nucleus that captures a stray neutron [in a nuclear reactor, for example] must bring the neutron to a stop within the diameter of the nucleus by means of the strong force.That force, which "glues" the nucleus together, is approximately zero outside the nucleus. Suppose...
  41. L

    Find the recoil velocity of the nucleus.

    Homework Statement An alpha particle is emitted from a stationary nucleus at 1.8 \times 10^7 ms^{-1}.The mass of the particle is 4u and that of the nucleus is 212u. (u is a unit of mass equal to 1.66 \times 10^{-27}kg.) (a) Find the recoil velocity of the nucleus. (b) Explain how you know the...
  42. M

    What's inbetween an atom's nucleus and electrons?

    If every thing's made up of atoms then that means air's made of atoms too so there can't be air between an atom's nucleus and electron so what is there? Nothing?
  43. A

    Is there a reaction called nucleus reaction?

    is there a reaction called nucleus reaction? my question is can we have reaction that has only the nucleus by separating the electron cloud and why we have in nuclear reaction most of the time reactions have the elecron in it and if we take the nucleus alone there will be no reactions having...
  44. E

    Calculating Alpha Particle Velocity from Initial Nucleus Motion

    CAN ANYONE HELP ME ? An automatic nucleus initially moving at 500 m/s emits an alpha particle in the direction of its velocity, and the new nucleus shows to 450 m/s. If the alpha particle has a mass of 4.0 u and the original nucleus has a mass of 222 u, what speed does the alpha particle have...
  45. X

    Calculating Zeff in Xenon (Z=54) for M (n=3) Shell

    Homework Statement In xenon (Z = 54), what is the effective charge Zeff experienced by an electron in the M (n=3) shell? Homework Equations Zeff = Z - total electrons in K and L shells The Attempt at a Solution I think total electrons in K shell are 8 and in L shell are 18...
  46. N

    An old nugget of a question: potential nucleus due to uniform charge sphere.

    Homework Statement Ast stated above: Biut i just can't get the correct answer! radius of sphere = a charge ze contained Homework Equations by gauss: E= (ze)*r/4pi(epsilon)*a^3 at any point within the sphere. and dv=r^2*sin(theta)dTheta*dphi*dr Energy density=...
  47. M

    Exploring Gamma Radiation in the Nucleus

    [SOLVED] Gamma radiation gamma radiation does anyone know how it is produced within the nucleus? and I know that gamma radiation takes place after a isotope has undergone a decay and is in an excited state. I know that what interest me is the very nature of the excited state! and how the...
  48. J

    How Large Can a Nucleus Get Before Instability Sets In?

    If a free proton is pushed to within 10^-13 centimeters of a nucleus, it overcomes the repulsion interactions and is locked into the nucleus. Is there a known limit to the size of a nucleus? Is there a limit to how many protons we can add to a nucleus? Thanks for your help John
  49. T

    Why Electrons Don't Fall Into Nucleus of Atoms

    Hi, Why the electrons in an atom doesn't fall into the nucleus? May be because of wave-like building of the electron? Thanks.
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