Nucleus Definition and 409 Threads

Homework Statement Well one of the questions that I'm not too sure the answer to is what parameter in the nucleus increases as a result of alpha and beta decay.Homework EquationsThe Attempt at a Solution Not too sure, I mean atomic number decreases and so does mass number so. But what...

If an electron does not orbit the nucleus in the classical sense, then how can we define an angular momentum operator that is analogous to the classical angular momentum? \hat{\mathbf{L}} = \hat{\mathbf{r}} \times \hat{\mathbf{p}} This angular momentum depends on both the position of the...

If nucleoli does not have a clear membrane,wouldn't it get mixed up with substances in the nuclear matrix present in the nucleus ?

My quantum textbook says that the probability of finding an electron in a 1s orbital between r and r+dr is given by Prob = (4/a^3)*(r^2)*exp(-2r/a) dr. In this case, Prob(0) = 0 because of the r^2, which is part of the volume element in spherical polar. Does this mean that it is impossible to...

Homework Statement Hi everyone. I'm a high school teacher. My background is physics and math, but right now I'm teaching a course that involves some basic (grade 10) biology. I don't know much about bio, so I need your help! Right now, we're studying the organelles. I'm trying to put together...

1. If we have sixty atomic nucleus that decay under ten days. How can we figure out their half life, their activity and a function? This graph shows how they decay: http://imgur.com/OSUB2P4 x axis illustrates times given in day, y-axis illustrates number of atomic nucleus decay2. No equations...

Homework Statement The formula being derived is N=No*e^k*t, from the equation Nn=No/2^n where No is the initial number of particles and the lowercase n in the second equation is the number of half lives. The n in Nn just indicates the number of particles after so many half lives. You might also...

For example, a cosmic electron projectile at 1TeV, is it possible to fly through a nucleus just like a bullet drills through a cake and makes the cake insensible recoil? After drill-trough, the electron may have some deviation from incident direction because the route may not exactly pass the...

How do we know that the nucleus is at the center of the atom? I know about the Geiger/Marsden experiment and also of its results. They observed a few α-particles scattering almost at 180°. Hence they concluded that there must exist a high density, positively charged "center" in the atom. But on...

I am trying to make some "longer" notes on how the findings of Rutherfords experiment. I have said that the nucleus was deemed to be positively charged because the alpha particles sometimes were deflected and did not continue on a straight path, and this is because of the repulsive force that...

Multiple_Authors submitted a new PF Insights post Why Don’t Electrons Crash into the Nucleus in Atoms? Continue reading the Original PF Insights Post.

Homework Statement An alpha particle (a helium nucleus, containing 2 protons and 2 neutrons) starts out with kinetic energy of 10.5 MeV (10.5x106 eV), and heads in the +x direction straight toward a gold nucleus (containing 79 protons and 118 neutrons). The particles are initially far apart...

Homework Statement A lead nucleus contains 207 nucleons (82 protons and 125 neutrons) packed tightly against each other. A single nucleon (proton or neutron) has a radius of about 1 ✕ 10^−15 m. (a) Calculate the approximate radius of the lead nucleus. (b) Calculate the approximate radius of...

Homework Statement I have the question with a diagram posted in the thumbnail to make things easier. Homework Equations E = mc² The Attempt at a Solution The homework only had a single example for a question like this so I am not 100% sure how to get the answer. So far I've added the 2...

Quarks join up with other quarks to form composite particles like protons and neutrons, but in the center of something like a nucleus, how do they know which quarks are in THEIR proton or neutron? When all the quarks are together and it becomes a "soup" of quarks, why doesn't it form things like...

Hi, I am new here. I am just reading over my notes for stable and unstable nuclei and I came across this sentence: 'Large nuclei require a higher neutron proton ratio as this adds more nuclear attraction without adding repulsion'. I was wondering why the large ratio would reduce repulsion? Thank...

The strong interaction keeps the quarks in very stable triplets or due to internal dynamics the quarks are re-arranged in nucleons from time to time?

Hi everyone: This concept has bothered me for a while. The concept being that two oppositely charged particles (electron and proton) are attracted to each other, but the electrons go on a orbital trajectory around the nucleus instead of directly "sticking to" the nucleus. The closest I have...

We often read that atoms are mostly empty space. A common example is given as, if the atom was a big as a football stadium the nucleus would be as big as a tennis ball on the center and nearest electrons circling around at far side of seats or something like that. How does this reconcile with...

Homework Statement If azXn is an unstable parent nucleus, write down expressions showing the products of the β + and β - decay of this nucleus. Homework Equations I have no idea how do do this, I recon its quite simple but.. Could anyone give me a pointer? The Attempt at a Solution none

Do the orbitals of electrons change positions within their energy level relative to the nucleus or are they statically "attached" to the nucleus? To try and put this into perspective, would the orbitals of the electrons be like nailing a balloon(orbital) straight to the ball(nucleus) or nailing...

Homework Statement If the size of the nucleus ( in the range of 10-15m to 10-14m) is scaled up to the tip of a sharp pin, what roughly is the size of an atom ? Assume the tip of the pin to be in the range 10-5m to 10-4m Homework EquationsThe Attempt at a Solution It's scaled up by a...

I am no Einstein but I would like to expand my knowledge and share it. When two deuterium atoms fuse together they become a helium nuclei. Now deuterium nuclei contains 1 proton and 1 neutron. When the deuterium nuclei fuses to form a helium nuclei. Helium nuclei contains 2 protons, and 2...

Protons and Neutrons vibrate in place, but do they change positions within the nucleus? Let's say that there's a helium atom which has two protons and two neutrons. If the particles were set up on the corners of a square for easy representation with a neutron on the top left and top right, and a...

Why distance of electrons from the nucleus is the same for same element?

Is it because the electron has less mass and is a point object that prevents it from falling into the nucleus due to attraction of protons?

Hi There! How a neutron is able to make a nucleus stable?

Hopefully I have this right. When they discovered the electron, they immediately realized that the electron should get sucked into the nucleus due to the electromagnetic force from the opposite charges. Why didn't they assume that the electron could orbit the nucleus to cancel out the...

I'm a little out of touch with this stuff , but I'm really not getting it.. So my book is considering: in a nucleus of ##z## protons, consider one proton in spherical charge distribution to other protons. So ## \rho = (z-1)e/(4/3) \pi R^{3}##, where ##R## is the radius of the nucleus, is the...

Mass of helium-4 (4.0015 u) plus mass of beryllium-8 (8.0053 u) gives 12.0068 u, which is 6.35 MeV above fundamental level of carbon-12. For triple alpha process T= 100 MK, which corresponds to a kinetic energy of 2 x 3/2 kBT = 0.03 MeV for the particles. This amounts to 6.38 MeV, way below 7.65...

I understand that there are many attempts from inside the nucleus to tunnel out therefore if it was just one alpha particle trying to get in it wouldn't happen. I'm struggling with this derivation from class to describe the number of attempts: How does a velocity and size of the nucleus...

I understand that having neutrons in nuclei creates additional strong nuclear force which brings protons together, overcoming EM force thus forming different atoms but why extra neutrons bring instability? Wouldn't more strong force mean extra "glue" to hold nuclei together? yet it seems N/P...

Homework Statement Nucleus ##^{252}_{98}Cf## alpha decays with half life time ##t_{1/2}=2.6## years. What is the velocity of the alpha particle after the decay? Estimate the half life time of the nucleus after the decay. Homework EquationsThe Attempt at a Solution Ok, no worries about the...

I am really not sure and do not understand how you find out what are the magic numbers in case of nucleus. Here in leson lecturer said that magic number is ##114##, and in other resourses I find number ##126##? Do we have any real confirmation of this?

Homework Statement A proton of mass m is moving with initial speed v0 directly toward the center of a nucleus of mass 31m, which is initially at rest. Because both carry positive electrical charge, they repel each other. Find the speed v' of the nucleus for the following conditions: a) the...

Homework Statement (a) What shows the existence of shell structure? What are the other numbers? (b) Deduce the spin and parities. Homework EquationsThe Attempt at a Solution The shell model is given by: So for Li, 3 protons pair up with 3 neutrons, leaving an unpaired neutron in...

Homework Statement An alpha particle with kinetic energy 15.0MeVmakes a collision with lead nucleus, but it is not "aimed" at the center of the lead nucleus, and has an initial nonzero angular momentum (with respect to the stationary lead nucleus) of magnitude L=p0b, where p0 is the magnitude...

Homework Statement I have been working some questions on decay but when i considered these 2 examples, there seems to be a problem Homework EquationsThe Attempt at a Solution Answer to first one is B while that of the second one is C. When I considered them separately, the answers seem ok...

As the title suggests. What is the space between the nucleus and electrons of an atom? Thanks

I have heard that instead of orbiting the nucleus they actually pop into and out of existence around the nucleus forming the electron cloud, and where they relocate depends on the probability of that area due to wave function, am i right?

If the electrons are negative charged and nucleus is positively charged, then why do electrons still orbit around the nucleus at a distance and not just stick to the nucleus?

So electrons were suppose to crash on nucleus according to classical physics. I want to understand the dynamics of it. The basic idea is that it will slow down as it emit photons. But with what force and mechanism? I think the answer is related with Abraham-Lorentz force, but i see too many...

Homework Statement calculate the mass of an unknown nucleus of mass M_X (initially at rest) if it it is hit by an alpha particle of mass m_xand is deflected by 40 degrees, and the alpha particle is deflected by an angle of 70 degrees. Assume elastic collisions [/B]Homework Equations...

1.Problem: An electron with energy ##E## which is much higher than its restmass collides with a much much heavier particle "A" of mass ##m## which is at rest. Find the maximal transfer of four-momentum. (Elastic collision)2. Conservation of four momentum3. Everything in natural units. So I go...

In all the places where Spin-Orbit interaction is discussed, the equations are derived by going to electron's rest frame and considering the interaction of nucleus' magnetic field with electrons spin magnetic moment. But from SR, we know that there as to be an explantion from the nucleus's rest...

Homework Statement There is this university exam question: Draw the nuclear binding energy curve and and show that energy is released when a heavy nucleus of A> 200 breaks up into two nearly equal fragments. Homework Equations See below. The Attempt at a Solution I found in an example in...

1. The problem statement, all variables and given/kown data Assuming that the nuclear radius R=γ0 *A(1/3) where γ0 =1.2×10(-15) and A is the mass number, Calculate the neutron and Proton densities in a nucleus N=Z. Homework Equations A=N+Z.=2Z in this case. Mass of proton =Z*mp Mass of...

Say we have a one dimensional chain of N mass points separated by springs of spring constant k. This system can be quantized? Let the quantized system above be at rest and let one of the end mass points emit a photon of energy E along the crystal axis. Will we get physics similar to he...

Hello there, Imagine that a nucleus consists of three atoms arranged in a equilateral triangle with the length of each side, ##R=2 \rm fm##. Our protons starts infinitely far away. What is the work required to push these protons together in order to overcome the electric force between them? I...

Homework Statement http://puu.sh/bz0km/092f2d8781.png Homework Equations h^2/2ma^2 The Attempt at a Solution I've found the uncertainty of the kinetic energy through many means, and I'm confident that it's .052MeV. The easiest method that gave me this answer was: using...