Helium Definition and 375 Threads

Homework Statement A neutron collides elastically with a helium nucleus (at rest initially) whose mass is four times that of the neutron. The helium nucleus is observed to rebound at an angle θ'2 = 41° from the neutron's initial direction. The neutron's initial speed is 6.2 x10^5 m/s...

Hey folks, I think this is the best section to ask this question. I've been thinking about the mining of He-3 on either the moon or the gas giants and the associated exorbitant costs, usually measured in the tens to hundreds of billions of dollars. I've also been trying to think of ways...

Is it easy to compress helium,not into a tank,just enough to make it heavier than air?and how much weight can it lift per cubic meter under normal atmospheric pressures? please can someone help!

I was watching a program "what would happen if" (or something along that line) in NatGeo and was stunned by what i saw in it. This is the situation. Several helium balloons are suspended from a car's roof panel through strings (interior of the car). When the car decelerates, what direction do...

Homework Statement The following elements should have optical spectra similar to either a hydrogen atom or a helium atom. Indicate which of the following elements should have optical spectra similar to a helium atom. (Select all that apply.) The choices are: Cadmium, Lithium, Technetium...

Homework Statement The mass of an unfilled balloon is 7.5g. How much helium has to be filled in the balloon to make it float in air? density of helium: 0.18kg/m^3 density of air: 1.29kg/m^3Homework Equations When I calculate the volume like this: (7.5*10^-3kg)/(0.18kg/m^3)=0.041m^3 and than I...

1. The problem statement, all variables, equations and given/known data ¨ Hi guys. I am working on solving the stationary Schrôdinger equation of the Helium atom by the variational method using a Slater determinant constructed from Slater type 1s orbitals, and in that respect i need to solve...

I just watched this Mythbusters video And he explains that the reason your voice gets higher when you inhale helium is because helium is less dense than air, so sound travels faster through it, making your voice higher. But wouldn't sound travel slower through a less dense gas?

if helium is 'superfluid' at low temperatures then is it correct to think of amorphous solids as 'superviscous'?

Could someone explain to me the reason why the 3d level of Singlet Helium is lower in energy than the 3p, since it is supposed to be higher because of less penetration...? The energy diagram is here: http://hyperphysics.phy-astr.gsu.edu/hbase/quantum/helium.html#c1 Thank you!

I'm trying to have a guest on the neutral Helium energy level diagram using the Bohr theory approach (just with n, does not include 2nd quantum number or spin). I think it should give me a close result. If not, I have to understand why. I went to NIST website...

I have a long, 24" diameter verticle pipe. There is a flow of gas through this pipe in which pure helium enters at the top and exits at the bottom where it exits to atmosphere. In this case, there must be a gradient of gasses with helium at the top and air at the bottom and a mixture between...

What is the rms speed of helium atom at 2000?

i want to know about the denisity of air and how does it exchange ... to use it in equation ...and the denisity of helium ... and how much do we need helium ( i mean volume ) to elevate 1 kg weight ... thank u sooo much

Homework Statement Helium in a steel tank is at 250kPa, 300K with a volume of .1m^3. It is used to fill a balloon. When the pressure drops to 150kPa, the flow of helium stops by itself. If all the helium is still at 300k, how big balloon is produced? Homework Equations I used the ideal...

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...

In atomic decay, when an atom decays and releases the (Alpha) Helium nucleus, the atom left behind changes to the element 2 Proton Numbers prior. So is this new element charged? because the electrons stay behind, or do they go? and if so, where to and how?

Homework Statement a) a light balloon is filled with 400m^3 of helium at 0 degree C, the balloon can lift a payload of what mass? b) what if? the density of hydrogen is nearly 1/2 the density of helium. what load can the balloon lift if filled with hydrogen? answer A) 444Kg B) 480Kg I have...

Homework Statement You blow up an ordinary party balloon with air until it has a diameter of 5.5 inches. Your friend blows up another balloon with helium gas until it has a diameter of 11 inches. Air consists mostly of O2 and N2 molecules, while helium gas consists of He atoms. Assume the...

Homework Statement What is the root mean square speed of Helium at 5K? Homework Equations Vrms=sqrt((3kbT)/m) The Attempt at a Solution I plugged all the numbers in and keep getting 7.19*10-12. The computer keeps telling me that it is not correct. The next question ask for the...

Homework Statement A certain organ pipe, open at both ends, produces a fundamental frequency of 291 Hz in air. If the pipe is filled with helium at the same temperature, what fundamental frequency fHe will it produce? Take the molar mass of air to be 28.8 g/mol and the molar mass of helium...

In a condition of high pressure, how could vary the Helium emission spectrum? Is this spectrum modified from the pressure?

Homework Statement Use the equivalence principle to explain the observation that a helium balloon leans forward in a forward-accelerating car. Homework Equations I don't think equations are needed. The Attempt at a Solution I'm completely confused on this question

If I filled a 4-5 foot piece of surgical hose with helium, would it stand vertically? How long would it remain assuming both ends were sealed? Would some other flexible material work better? A balloon on a string would not work for my purpose. Thank You

I am a freshman and in physical science but we have not yet come to fusion or anything like that. One day I just started to think.. what if you took an ordinary hydrogen atom (not an isotope.) and added 1 proton, 1 electron, and 2 neutrons in whatever way you could. Would you get helium, or just...

E=1/n^2 (-13.6eV) for other one-electron atoms –ionized helium (Z=2), doubly-ionized lithium (Z=3),etc. I found contradicting here is that one-electron atom and Z=2, 3. If it’s one electron, then there is only one proton, so where do 2 or 3 protons come from? Thanks.

i am having a bit of trouble with this question, and its not explained very clearly in our textbook... "what are the RMS speeds of helium an dargon in a gas at 1000 degrees C" any help would be greatly appreciated. physics is definitely not one of my strengths... =D cheers. KC

Homework Statement Calculate the energy and radius for each of the five lowest (n = 1,2,3,4,5) electron orbits in a Helium atom with only one electron. Enter the energy as a positive value in units of "eV" and the radius in units of "nm". Hint: The Helium nucleus has 2 protons so Z = 2 and...

Hey all, I just discrovered these forums, thankoodness, because I'm taking physics over the summer (its a requirement at my school), and not being a science-y person, I really need help. Homework Statement [/B] This is the problem: Problem 1 a. What is the average translational...

I'm using McQuarrie's "Quantum Chemistry" book for a little bit of light reading. He included a proof of a theorem that states that if a Hamiltonian function is separable, then the eigenfunctions of Schrodinger's equation are the products of the eigenfunctions of the simpler "separated"...

Hia, I am not a student, I am a gas engineer in the UK. Had a thought and tried out some theory but didn't get very far. Basically; if a helium balloon rises in air as it is lighter than the air it displaces, what if I could get a tube (say internal dimensions of 15mm in diameter and 1000mm...

h ttp://en.wikipedia.org/wiki/Superfluid Wikipedia states that, in the context of superfluids: I assume what is meant is that the atoms have bosonic an fermionic properties under super-cooled conditions. I gather that the spin of the constituents of the atom (protons, neutrons...

If we were to inhale some Helium and speak, our vocal frequency will get higher producing high pitch and often comical tone. It's due to the different wave travel speed in Helium gas compared to air which results a bigger frequency according to V=wave length x frequency What if we filled a...

Homework Statement The mass of silicon in the Earth is estimated to be 7x10^23 kg. The ratios of the masses of Hyrdogen and Helium to silicon in the sun are: H/Si = 850, He/Si = 250. Calculate the mass of the the body thatwould have been produced if H and He had been added to the Earth...

Hi all! I just joined the forums and hopefully my question is in the right place and isn't a lame one but I'm stuck so here goes: I want to know how to calculate wavelength from a known distance and color for Helium. I need exact wavelength. I already have the ranges obviously. Usually...

If I were to let go of a Helium balloon with a volume of 3 liter at a depth of 10 meters, how do i calculate te time it will take the balloon to reach an altitude of a 100 meters in the air? And what changes if its not helium but hydrogen for instance? hope anyone can help me with this

Would a tuning fork in an atmosphere of Helium sound different than in air? I know the speed of sound is much faster and the fork (100Hz) would have a different wavelength but how would that affect sound?

What's the purpose of the regulated helium source going into the solvent reservoirs in HPLC? Is it just to degas the solvents? Does it have any other use?

Homework Statement A light baloon filled wiht helium and with a density of 0.180kg/m^3 is tied to a light string of length L= 3.00m. The string is tied to the ground, forming an "inverted" simple pendulum. The balloon is displaced slightly from it's equillibrium position, as shown in picture...

Homework Statement What's the polarizability of liquid helium given: density= 145kgm^-3 relative permittivity = X = 1.0566 Homework Equations alpha (polarizability) = (3(permittivity of free space))/N) / ((X-1)/(X+2))The Attempt at a Solution because N is molecules/volume...

Homework Statement When you sing, the vocal folds in your throat act as a resonating cavity (one open end, one closed end) which allows only certain frequencies. Suppose you try to sing a pure tone which is detected by a microphone and measured to have a frequency 500.0 Hz. This is the...

Homework Statement A light spring of constant k= 90.0N/m is attatched to a table vertically. A 2.00g balloon is filled with helium (d= 0.180kg/m^3) to a volume of 5.00m^3 and is then connected to the spring, causing the spring to stretch as shown. Determine the distance L when the balloon is...

Homework Statement An empty rubber balloon has a mass of .0120 kg. The balloon is filled with helium at a density of .181 kg/m^3. At this density the balloon is spherical with a radius of .500m. If the filled balloon is fastened to a vertical line, what is the tension in the line...

Homework Statement I have a balloon with helium in it, I need to know the acceleration that it rises. It would be great if you could tell me what I need if I am missing any. This is what I have, Density of liquid(air) = 1 g/l Density of Helium = .1786 l/g Volume of Balloon = 91 cubic...

This is my first post here so hello to anybody who reads this! I just finished calculus based physics II this semester and there are a few things I want to design and make for myself to help better my understanding of what I learned in physics. One is device I have seen that generates an...

Suppose the neutron decay time n was 89 sec. AND the difference in rest mass between neutron to proton, Qn, was 0.129 MeV. What would the maximum Helium fraction, Yp, be?

[SOLVED] Helium and Balloons/Pressure Homework Statement A tank having a volume of 0.100 m3 contains helium gas at 120 atm. How many balloons can the tank blow up if each filled balloon is a sphere 0.300 m in diameter at an absolute pressure of 1.35 atm? What i know: V(tank)=.1m^3...

From Classical Mechanics by Taylor: "The Compton generator is a beautiful demonstration of the Coriolis force due to the Earth's rotation,... A narrow glass tube in the shape of a torus or ring (radius R of the ring >> radius of the tube) is filled with water, plus some dust particles to let...

Hi! I have a project where I am supposed to model the s-process in a star in its Helium shell burning region, and i shall do this for a variation of neutron exposure, where neutron exposure are defined as: \tau = N* \Delta t , t is time. N is number density of neutrons. So I in...

Homework Statement What is the RMS speed of Helium atoms when the temperature of the Helium gas is 247 K? (Possibly useful constants: the atomic mass of Helium is 4.00 AMU, the Atomic Mass Unit is: 1 AMU = 1.66×10-27 kg, Boltzmann's constant is: kB = 1.38×10-23 J/K.) What would be the RMS...