Helium Definition and 389 Threads

  1. Sebastiaan

    Helium 3 breeding in fusion reactors

    There are several fusion reaction which produce Helium 3 as ash 1) D + D => T + p / He-3 + n 2) p + Li-6 => He-4 + He-3 3) p + D => He-3 + photons Assuming we can create and maintain these fusion reactors. Would it be possible to to collect the Helium3 from the fusion tractor...
  2. avito009

    Is Proton Mass Really Reduced in Helium Nuclei?

    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...
  3. Y

    IGCSE Physics Boyle's law question

    Homework Statement The helium in the cylinder has a volume of 6.0 × 10^–3 m3^-1 (0.0060 m^3) and is at a pressure of 2.75 × 10^6 Pa. (i) The pressure of helium in each balloon is 1.1 × 10^5 Pa. The volume of helium in an inflated balloon is 3.0 × 10^–3 (0.0030 m3). The temperature of the...
  4. N

    A question for helium energy transition

    For S=0 parahelium, 1s2p-1s2s transition is allowed, but why there is no transition between 1s3p-1s3s? I think the only difference for the electron configurations is principal quantum number. The selection rules applying for 1s2p-1s2s can also be applied to 1s3p-1s3s. In other words, there is...
  5. T

    How Large Must a Helium Balloon Be to Achieve Neutral Buoyancy?

    Homework Statement What diameter must a helium filled balloon have to float with neutral buoyancy? The mass of the empty balloon is 2 g. Homework Equations FB = (density)(gravity)(Volume) Volume of balloon = 4/3(4.13)r^2 Density = mass/Volume The Attempt at a Solution I know that the...
  6. Davephaelon

    Transferring Liquid Helium to Another Container

    I have a small 'cryostat' which I would like to fill with liquid helium to conduct an experiment. It consists of a circular plastic kitchen measuring cup 3 inches wide at the top, 2 and 1/4 inches wide at the bottom, which is flat, and 1 and 1/2 inches deep. The plastic wall/floor is about...
  7. M

    Gas in a semi permeable membrane - one for the gas experts

    I believe I know the answer to this question; I need an expert to verify it for me. I work for a company that makes latex balloons. The people that have been here for a long time insist that if one is putting a small (5" balloon) filled with helium inside a larger (30") balloon then one must...
  8. B

    Variational method For Helium Atom

    When using the variational method for the Helium atom, we determine that the lowest possible energy occurs when 1<z<2 where z is the atomic number. My professor elaborated that the number is within this range because there is a probability that the electron may be so close to one of the protons...
  9. G

    Spectrum of singly ionised helium

    Dear Friends! We know ionized helium has two protons in its nucleus, whereas hydrogen has one. This changes the line spectrum completely. Why? Thank You in advance!
  10. R

    Moles of gas helium balloon; buoyancy; PV=nRT

    Homework Statement A helium balloon is used to lift a load of101N. The weight of the envelope of the balloon is46.5N and the volume of the helium when the balloon is fully inflated is31.5m3. The temperature of the air is 0°C and the atmospheric pressure is 1.00 atm. The balloon is inflated with...
  11. physicsisgreat

    Units in quantum mechanical problem about 4-He

    Homework Statement Units of the problem are chosen to be such as KB = 1 and ħ = 1 so that energies are expressed in Kelvin and lengths in Å. The professor says the resulting value of ħ2 / 2 m for a 4-He atom is 6.0599278: how is that possibile? Homework Equations Natural units websites give...
  12. U

    Anti-symmetric and Symmetric Helium

    Homework Statement (a) Find the spatial wavefunction (b)Show anti-symmetric wavefunctions have larger mean spacing (c) Discuss the importance of this (d)Determine the total orbital angular momentum (e)Hence find the ground state term for Z=15[/B] Homework EquationsThe Attempt at a Solution...
  13. J

    Triplet and Singlet Helium States

    I have a theoretical question, I just recently learned that the spin triplet S=1 of helium in the state 1s2s is lower in energy than the 1s2 state due to the exchange interaction. I then learned that this 1s2s state has a shorter lifetime than the 1s2 state, can anyone explain why this occurs...
  14. J

    Two particle wavefunctions of helium

    Homework Statement The two-particle wavefunctions are given: Where |V> is the spin down state and |Λ> is the spin down state ½(Ψ3p(r1)Ψ1s(r2) + Ψ1s(r1)Ψ3p(r2))(|V>|Λ> - |V>|Λ>) ½(Ψ3p(r1)Ψ1s(r2) - Ψ1s(r1)Ψ3p(r2))(|V>|Λ> + |V>|Λ>) 1/√2 (Ψ3p(r1)Ψ1s(r2) - Ψ1s(r1)Ψ3p(r2))(|Λ>|Λ>) 1/√2...
  15. AdityaDev

    Expansion of a Helium-Filled Balloon: Exploring Thermodynamic Processes

    If I heat a rubber balloon filled with helium slowly and if the balloon is fully expandable and (the balloon) can be assumed to require no energy in its expansion,what type of thermodynamic process is taking place? Is it isobaric? Since the balloon expands the pressure exerted by the gas on...
  16. L

    Liquid helium - Siemens-cycle only?

    Why can't I reach 4K with the Siemens-cycle?
  17. S

    Calculate velocity of helium baloon

    Problem statement: A Helium filled balloon has a volume of 1 cubic meter and a mass of 0.200 kilograms. It is released and rises through the air because of its buoyancy. The buoyant force is equal to the weight of air displaced by the balloon.. This force is given by: F_b = [1.29e^(-1.21h)]g...
  18. J

    What fraction of the Sun’s total mass is lost during fusion?

    Homework Statement During fusion of hydrogen to helium, 4 billion kg of matter are converted to energy each second. What fraction of the Sun’s total mass is lost each year to this process? Homework Equations None. The Attempt at a Solution First: Convert how many seconds are there in a year 1...
  19. L

    De Broglie wavelength of helium atoms

    Homework Statement a) In the double slit interference pattern for helium atoms, the kinetic energy of a beam of atoms is 0.020 eV. What is the de Broglie wavelength of a helium atom with this kinetic energy? b) Also, estimate the de Broglie wavelength of the atoms from the fringe spacing...
  20. dontbearrogant

    Helium Ion Particle Accelerator

    Okay you're going to have to forgive me but I'm new to all of this and I'm still getting a hang of this website(as well as having little or no education/experience in much of any physics beyond high school),but I was wondering if it would be possible to make a particle accelerator that used...
  21. Y

    Helium formation during nucleosynthesis

    If Helium is a more stable element than Hydrogen, then why wasn't just Helium formed during the process of nucleosynthesis? The matter could just have formed Helium. What was the thing that prevented it?
  22. S

    Why does superfluid helium in a spinning bucket have angular momentum?

    Suppose you have a bucket filled with superfluid Helium-4 and you spin it with a large angular velocity Ω, the bucket obviously has angular momentum. Spinning fast enough, the fluid develops irrotational vortex lines which carry quanta of angular momentum, while leaving the curl of the ∇xv 0...
  23. Physicist50

    Helium Plasma Reaction: Magnetic Field Impact

    Hello everyone, I was recently creating two different types of plasma for a Science Fair, one created from ionised Helium, (although it's the party balloon stuff, and I hear there's some Oxygen in them) and the other was created from air. I was testing how the plasmas reacted to magnetic fields...
  24. S

    Helium Atomic Structure: Ionization Speed Compared to Air

    Would helium take less time to ionize than air, because it expand faster when heated up?
  25. S

    Comparing Helium & Air Plasma in a Science Fair Experiment

    After a science fair experiment we have measured the similarities and differences of plasma created by air and helium. Our methodology is as follows. Methodology A(air): 1. Light a match and place it on a small raised surface inside a microwave 2. Cover the match with a glass bowl/beaker...
  26. S

    Is It Safe and Feasible to Create Plasma in a Microwave Using Helium Gas?

    For a science fair experiment me and my partner are working on creating plasma in a microwave.Our hypothesis is that if the manipulability of plasma is affected by the type of gas used, then plasma will react to magnetic fields differently depending on the gas that has been ionised. Because...
  27. R

    Volume of a helium baloon inside a fridge

    If a helium-filled balloon initially at room temperature is placed in a freezer, will its volume increase, decrease, or remain the same? The Attempt at a Solution If you decrease the T of a vessel filled with gas, its molecules will have less kinetic energy, and the pressure inside the...
  28. P

    Would there be any use in a Rydberg equation for Helium

    In high school I took an advanced physics class, in which we learned the Bohr Derivation, after the lesson my teacher then drew a model of Helium then explained that no one however had come up with the equation to represent the spectral lines of Helium, so i had taken on this challenge to see if...
  29. S

    Finding the Current for a Plasma Creation in Helium

    Hi all. I am currently trying to determine the specifications of equipment I need to create a plasma. I am looking to generate a plasma in chamber of Helium at a pressure of about 0.6 Torr. My electrodes are around 17cm apart (giving me a pd of 10 Torr cm). By consulting Paschen curves, I see...
  30. tridianprime

    Solid Helium: Why No Images? | Feynman Lectures Vol.1

    I was not sure exactly where to put this but it involves images so I thought it was no too inappropriate here. I was reading the Feynman Lectures Vol.1 and he says that Helium, although not solid at absolute zero normally, can be so in high pressures. I then googled this for images but none...
  31. E

    The ground state of helium - showing that parhelium is ground state

    Homework Statement The Hamiltonian of helium can be expressed as the sum of two hydrogen Hamiltonians and that of the Coulomb interaction of two electrons. \hat H = \hat H_1 + \hat H_2 + \hat H_{1,2} The wave function for parahelium (spin = 0) is \psi(1,2) = \psi_S(r_1, r_2)\dot...
  32. M

    Calculating the % hydrogen and % helium

    Hello, I have been studying the early universe where everything was a bunch of hydrogen atoms and helium atoms. Apparently they calculated the %composition of the universe at the time. How did they do that? What sort of equations can be used to calculate these quantities?
  33. D

    Why does nitrogen gas' pressure not change after an addition of helium

    a 9 L vessel contains 3 moles of helium and 3 moles of nitrogen at a pressure of 10 atm. Maintaining constant temperature, an additional 2 moles of helium are added. Assuming gases behave ideally, what are the partial pressures of nitrogen and helium at the end? Initially there's: 3mol He/(3mol...
  34. E

    Magnetic moment of singly ionized helium

    Homework Statement Find the magnetic moment of singly ionized helium in terms of Bohr Magneton I know the expression for the Bohr Magneton -- I am not trying to get a walk-through here as I want to do this myself, but I just want to know if I am correct in assuming that to get the problem...
  35. M

    Why does water have higher entropy than helium?

    Hi, Under standard conditions, why does water have higher entropy than helium? Isn't helium a gas? I understand that water has more atoms, but it seems more ordered and is a liquid. I'm not sure how a qualitative analysis could lead to the conclusive result that water is higher in entropy...
  36. C

    How can I differentiate between alpha particles and helium in an enclosed space?

    Can someone recommend (if possible) a way to detect the amount of helium in a given enclosed space? I'm designing an experiment in which I will need to measure the amount in an otherwise vacuum.
  37. L

    Impact of Helium 3 from Extraterrestrial Sources

    Can bringing a surplus of Helium 3 from a Extraterrestrial source effect our Earth's ecological balance? Has there been any studies on this?
  38. A

    Calculate the final temperature of the helium

    Homework Statement A rigid cylinder contains helium (molar mass 4kg/kmol) at a pressure of 5 bar and a temperature of 15 oC. The cylinder is now connected to a large source of helium at 10 bar and 15 oC, and the valve connecting the cylinder is closed when the cylinder pressure has risen to...
  39. Gh778

    Liquid helium and curved piston

    It's a theoretical study. Like the image showing, the curved piston move in container and need energy for that. In the same time, another piston move up and recover energy. The pressure inside container is always the same (need to control speed of pistons, but there is a pressure). No gravity...
  40. M

    Does Helium or Hydrogen have the greater atomic radius?

    I've been looking online at multiple resources and seem to be getting conflicting answers. http://www.sciencegeek.net/tables/AtomicRadius.pdf - Where He is slightly smaller than H http://intro.chem.okstate.edu/1314F00/Lecture/Chapter7/ATRADIID.DIR_PICT0003.gif - Where H is smaller than He...
  41. K

    Helium: Graph of Root Mean Velocity vs Temperature

    I'm looking for a graph that shows me the root mean velocity as a function of temperature for helium gas. Does anyone know where I can find this? Thanks.
  42. L

    How Do You Calculate the Bohr Radius for a Helium Ion?

    Homework Statement Using the Bohr model, find the atomic radius for a singly ionized He+ atom in the n = 1 (ground) state and the n = 2 (first excited) state. Then find the wavelength of the emitted photon when an electron transitions from the n = 2 to the n = 1 state.Homework Equations a_0 =...
  43. C

    How to detect neutrons using Helium 3

    I understand that helium 3 has a very high probability of fusing with thermal neutrons, and the reaction produces tritium and hydrogen: n + 3He → 3H + 1H + 0.764 MeV however I do not understand how this reaction is detected. Can someone please explain? Thanks.
  44. F

    How Many Balloons Can You Inflate with a 15L Helium Cylinder?

    Homework Statement A cylinder containing 15L of helium gas at a pressure of 165 atm is to be used to fill party balloons . Each balloons must be filled to a volume of 2L at a pressure of 1.1 atm. What is the maximum number of balloons that can be inflated? (Hint: the empty cylinder will...
  45. Crazymechanic

    Fusion reactor helium poisoning

    Hi I have a question , now in fusion reactors like a tokamak design and also in others , if they use say the deuterium tritium mixture as fusion fuel which ends up in some released binding energy , alpha particles, a energetic neutron etc. Now the neutron and alpha particles an d all other stuff...
  46. B

    Exploring Alpha Decay: The Science Behind Helium Nucleus Emission

    Why does alpha decay emit a helium nucleus.Why not a proton or gamma rays. Please help me understand the science behind why it emits this?
  47. O

    My idea for a helium generator

    Hello. I am currently doing my GCSEs and I take Triple Science. My favourite science is definitely physics, and after a lesson on radioactive decay at school I came up with an idea. I remember a while ago hearing on the news that the Earth is running out of natural sources of helium. My idea...
  48. A

    Lift of a helium spherical balloon

    So I was pondering this question: On a conceptual level, how does a perfectly spherical helium balloon rise? I understand that the density of helium gas is lower than that of our atmospheric composition of gases, but that is not giving the full perspective for me. On a molecular level, I feel...
  49. C

    How can Helium 4 be a Boson and Helium 3 be a Fermion?

    Hi there, Just a quick question which I'm sure I'm over complicating in my head.:confused: I've read that Helium 4 is a Boson because it has 0 spin and that Helium 3 is a Fermion because it has 1/2 spin. Is this right? I don't see how whole atoms can be associated with fundamental particle...
  50. H

    Thermodynamics Problem involving an ideal gas Helium?

    Hi guys i am new here hope you are all well, had a problem with a physics question hope you can help. Helium gas m=2.0(g) is at an initial temperature T1=100 degreees and initial pressure P1=100000 Pa, and has a volume V1. The gas undergoes isobaric (P=constant) expansion until its volume is...
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