Questions tagged [binding-energy]

Please use binding energy in the context of the atomic scale and/or atomic systems. This can be used in nuclear reactions.

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331 views

Does the mass of object really increase?

We were taught the concept of binding energy, We first started with the example of two blocks with some masses having a spring between them. And now they are released from their position, As they ...
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How much pressure can a single atom sustain before it collapses? [closed]

How much pressure can a single atom sustain before it collapses?
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Beryllium(8) Never exists! [duplicate]

Why does Be(8) never exist and decay into 2 alpha particles? Here, given Binding energy of Be(8)=7.064MeV & Binding energy of He(4)=7.08MeV.
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Why does binding energy have an affect on measured mass?

I've looked into how the binding energy functions and that increasing the particles' potential energy or their distance from the other particles increases the mass of the system. My question is why ...
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What is wrong with this calculation of gravitational binding energy?

As far as I understand it the gravitational binding energy of some distribution of mass is the negative of its gravitational self-potential energy. I tried to calculate the latter for a solid sphere ...
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Binding Energy and Instability

I believe that I am correct in saying that: (1) a nucleus constitutes a preferred configuration for nucleons as compared to a disassembled array of nucleons; and (2) nuclei decay so as to achieve more ...
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Negative or positive binding energy?

I'm working with modern physics atm, and can't seem to wrap my head around the binding energies of some molecules. At first, I thought that a negative binding energy = unstable molecule, and a ...
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54 views

why does the brehmsstrahlung continuum of a particular anode material extend beyond the k-alpha and k-beta energy level of that material?

I was looking at the excitation spectrum of a few elements in the first page of this document: http://www.amptek.com/pdf/Choosing%20the%20anode%20material%20in%20an%20x-ray%20tube.pdf In particular I ...
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660 views

Calculating the unified atomic mass unit [duplicate]

The masses of electron, proton and neutron (in SI units) are (approx.): \begin{equation} m_e=\text{electron mass}=9.109\times 10^{-31}\ \text{kg} \end{equation} \begin{equation} m_p=\text{proton mass}...
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Why does fusion use mass for energy?

I have the basic idea: for small nuclei the mass of product is less than the mass of the individual pieces, this mass is released as energy via $E=mc^2$. But why do nuclei use the mass for energy? ...
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Can daughter nuclei from fission be lighter than Fe-56?

In a typical nuclear fission reaction, a heavy nucleus decays into daughter nuclei which are lighter and have higher binding energy per nucleon. For example: ...
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496 views

When does semi-empirical mass formula break down?

When does the semi-empirical mass formula stop working and what are its limitations? Is it when the difference in $N$ and $Z$ becomes large or when atoms become too big?
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Comparison between Bethe-Weizsäcker-Model for the nuclear binding energy and measurements

I tried to compare the binding energies of between the measured data and the Bethe-Weizsäcker model. My plot looks like this and I don't understand the large discrepancy: For the measurement I used ...
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Where does mass deficit energy go?

I get the idea (at least, as much as a layperson can) that a helium nuclei has less mass than the sum of its parts. That mass deficit is turned into energy. At this stage I feel like I've heard two ...
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Why is the total energy of an electron in an atom negative? [duplicate]

Why is the total energy of an electron in an atom negative? We know that $$E = -\frac{e^2}{8\pi\epsilon_0a_0}.$$ What does the negative sign in the above equation means?
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Calculating energy released by using binding energy VS mass difference

Please take a look at (C). I have no prob with (a) and (b) but some values are needed from (a) and (b) in order to perform a calculation in (C). For (C), I wonder why I got different answers from two ...
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Alpha decay condition using semi-empirical mass formula

I have to find a equation of Z as a function of A, where Z denotes the atomic number and A denotes the mass number of an atom, for odd-even nucleii which can barely undergo alpha decay (by themselves) ...
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1answer
498 views

Can heavy elements be fused? [duplicate]

Yes, I know, in stars, fusion occurs up to Iron(-56); but, I want to know if fusion past this nucleus can happen at all. If so, the daughter element would move to the right of the peak and its ...
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562 views

Energy release with hydrogen fusion

$$H_1^2 + H_1^2 \rightarrow He^4_2+ \text{energy}$$ How can energy be released, if the left hand side of this equation has less mass/energy than the right? $\text{BE}_H \approx 1 \text{MeV}\\ \text{...
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From where does the binding energy come from always to bind the nucleus?

Inside the nucleus there would always be the repulsive forces. The binding energy puts the nucleus binded but the energy eventually gets exhausted, but the repulsive forces are ever lasting. To bind ...
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If Hydrogen's nucleus lacks a neutron, then what is keeping the nucleus stable and the proton inside it?

I have two questions : In a simple hydrogen atom $(^1_1H)$, there is no neutron. So, if there is no nuclear force to hold the nucleus together then what is the thing that is holding the atom together?...
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838 views

Energy released in nuclear fission

In induced fission of U-235, neutrons are bombarded at the U-235, producing U-236. This U-236 then undergoes fission: U-235 + n --> U-236 --> Ba-141 + Kr-92 + 3n As far as I understand, the energy ...
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Why do nuclei decay so fast and slow?

Why do nuclei like Oganesson (also known as Ununoctium, this is the 118th element on the periodic table) decay in about 5 milliseconds? This is weird that they decay. In comparison, why do elements ...
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785 views

Binding energy converted to kinetic energy/mass loss

My particular question is regarding nuclear fission, but applies to other nuclear processes as well. I understand that in nuclear fission, the two fragment nuclei have a higher binding energy per ...
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Why are there no stable isotopes with an atomic mass of 5 or 8?

One of the things I've encountered in my travels is the mass-5 roadblock. Rod Nave writes about it on his excellent educational hyperphysics website: The helium-4 nucleus or alpha particle with a ...
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563 views

What holds metal atoms together? And what accounts for the strength of metallic bonds?

From the wikipedia page for metallic bonding, I've noticed that there seem to be a few things at play: (1) the delocalization of electrons, and (2) the fact that there are a far larger number of ...
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1answer
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How do we know which lighter elements fuse to form heavier elements?

Formation of lighter elements is fairly straightforward: He + He + He = C-12. However for each heavier element (heavier than Fe in particular), is there exactly one combination of (two lighter) ...
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Energy conservation in radioactive decay

To show my current understanding, I'll use alpha decay as an example and list my questions at the end. Could you please correct me if I'm wrong. An alpha particle forms in the parent nucleus. It's ...
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How does the semi-empirical mass formula prove or detract from the existence of the “valley of stability”?

I came across this passage in my lecture notes. The semi-empirical mass formula (SEMF) is a better estimator of atomic mass than the standard mass formula, which neglects spatial arrangement of ...
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In what way is mass converted into energy in nuclear reaction?

My book says: In nuclear reactions, the number of protons and the number of neutrons are the same on the two sides of equation What I have read: The total binding energy of nuclei on the left ...
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1answer
179 views

Binding energy per nucleon error

I am given that the mass deficit of 114-Cd is -90.01 MeV, and asked to calculate the binding energy, which should simply be 90.01 MeV then, due to the use of natural units (i.e. where $c=1$). I'm then ...
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198 views

Sum of nucleus less than sum of neutrons & protons? [duplicate]

The mass of a nucleus is less than the sum total of the individual masses of the protons and neutrons which form it. How this is possible?
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About the Stability of hydrogen Isotopes

Shouldn't tritium be more stable than a hydrogen atom with no neutrons? Why does tritium do alpha decay but not hydrogen atom with no neutrons? I suppose that when the number of neutrons increases the ...
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Why plutonium and uranium are especially susceptible to do fission?

Why plutonium and uranium are especially susceptible to do fission? Are there any other elements that can also be subject to fission?
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Why is the exciton binding energy slightly smaller than the band gap energy?

In a semiconductor it requires energy equivalent to the band gap energy ($E_g$) to excite an electron to the conduction band. This gives rise to an exciton (conduction electron-valence hole pair). The ...
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What type of energy released from Nuclear Fission

My physics book mentions that its kinetic energy being released from the splitting of atoms, but it makes more sense for it to be heat energy as the construction of a power plant as shown below is ...
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What is Binding energy/the energy required to for a nucleus to form a result of?

Is it simply the work required to overcome the electrostatic repulsion of protons, or rather the coloumb barrier potential between nuclei? If so where does the effective of tunneling come in, as ...
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Why is hydrogen or helium used in nuclear fusion?

I am not a Physics student. Just out of own interest, I'm studying about fission and fusion reactions. Where I found in fusion, the scientist are using either hydrogen isotope or helium-3 as fuel (...
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1answer
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Why must nuclei contain both protons and neutrons? [duplicate]

In most atomic nuclei there are both protons and neutrons. Having a poor understanding of the strong interaction, it puzzles me why a nucleus must consist of both. Namely, why can there not be ...
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Why is there a mass defect in nuclear fusion? [duplicate]

So I'm currently trying to wrap my head around nuclear fusion, but there is something that keeps bugging me: I've read in many places that when two hydrogen atoms combine, the resulting helium atom ...
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1answer
104 views

Error in calculating binding energy of Beryllium 8 [closed]

I don't know where I am going wrong with regards to calculating the binding energy of $^8$Be. This is what I am doing: I look up online and find that the mass excess of $^8$Be is $5305 \mu$u. Thus, ...
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How is binding energy actually measured?

How, exactly does one measure binding energy? Or, assuming binding energy is calculated from mass defect and $E = mc^{2}$, then, how is mass defect measured? I know one can be calculated from the ...
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Neutron star material [duplicate]

A neutron star is created by the gravitational collapse of a massive star. The atoms are pushed into each other, the electrons into the protons etc. and it is held there under the existing ...
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1answer
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Whether mass defect can be restored its original level?

If two stick two magnets the mass will be less than sum of the individual magnets. They lose certain mass while they stick together. Probably, they release some energy. My question is: when the ...
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Would small quantities of neutronium be stable?

Considering the fact that naturally occurring neutronium, or neutron degenerate matter is created by stars more massive than the sun, it is apparent that electron-degenerate pressure is difficult to ...
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Where does energy come from in a nuclear fission if nucleon count doesn't change?

In a nuclear fission the total number of protons and neutrons are conserved. Then the mass converted to energy $E=mc^2$. From where this mass come from? Does that mean that all protons and neutrons ...
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1answer
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Why don't the nucleus break apart? [duplicate]

The nucleus of an atom is made up of protons and neutrons. So if there are many protons inside nucleus even though there are neutrons why don't this protons may repel away breaking nucleus apart? The ...
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510 views

Basics questions about the strong force

I have what is probably a bitter misconception about the strong force which I would like to clarify. Here's my (probably flawed) reasoning. The strong forces holds protons and neutrons together at ...
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1answer
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Why is Helium an anomaly on the binding energy curve?

So I'm failing to understand why helium is anomalous on the binding energy curve. I know it includes concepts such as pairing, shell correction, and the liquid drop model. However, these were simply ...
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872 views

What is the energy transformation in the fission reaction?

According to one of my physics textbooks, when U-235 absorbs a neutron it becomes unstable and soon fissions into two separate atoms. The forces driving these two atoms apart are electrostatic forces ...