Mass Of Neutron In Kg

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  1. Mass Of Neutron In Kg
  2. Mass Of A Neutron Star In Kg
  3. Mass To Kilogram

In astronomy, large masses are usually measured in solar masses; one solar mass is equal to the mass of our sun (1.9891 x 10^30 kilograms). A typical neutron star has a mass between 1.3 and 2.

San José State University

Kilogram to neutron mass (kg—) measurement units conversion. The SI unit of mass is a kilogram, which is defined by taking the fixed numerical value of the Planck constant h to be 6.626 070 15 × 10⁻³⁴ when expressed in the unit J s, which is equal to kg m² s⁻¹, where the meter and the second are defined in terms of c and Δν Cs. The neutron has a mass of 1.67 × 10 –27 kg. Neutrons emitted in nuclear reactions can be slowed down by collisions with matter. They are referred to as thermal neutrons after they come into thermal equilibrium with the environment. The average kinetic energy ( 3 2 k B T ) d of a thermal neutron is approximately 0.04 eV. Definition of neutron. A neutron is a neutral sub-atomic particle, which is found with a proton in the nucleus of an atom. It is represented by the N 0 sign. The number of neutrons present in an element determines the mass of that element. Mass of neutrons. The mass of a neutron is about 1.675 × 10 −27 kg or 939, 565, 413.3 eV / c 2, or 1.

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Relative Particle Sizes
Based on Equal Mass Densities

Particle Sizes

There are creditable estimates of the sizes of a neutron and a proton.

The radius of a proton is about 3/4 that of a neutron.

Mass Of Neutron In Kg

But the sizes of the rest of the subatomicparticles are a great mystery, even that of electrons. An internet search for the size of an electron brings up assertionsranging from an electron being three times the size of a proton down to it being one one-thousandth of that size.

The rest masses of all charged particles are known from the curvature of their trajectories in a magnetic field.

It is quite plausible that the mass densities of all subatomic particle are the same. If that is the case then thethe ratio of the radii of two particles is equal to the cube root of the ratio of their rest masses.

The Size of an Electron

The mass of a proton is 1836 times that of an electron. Let Rp and Re be the radii ofa proton and an electron, respectively. Then

Rp/Re = (1836)1/3 = 12.245

Here is a depiction of their relative sizes.

with the proton shown in red and the electron in blue.

Since the accepted radius of a proton is 0.8768 fermi this makes theradius of an electron 0.0716 fermi.

The Leptons

There are three types of leptons and their antiparticles: the electron, the muon and the tauon.But a muon has a mass 207 times that of an electron,If the muon has the same mass density as the electronthen the ratio of their radii is given by

Rμ/Re =` (207)1/3 = 5.9155

On the other hand, the tauon has a mass 3477 times of an electron.thus the ratio of the their radii is

Rτ/Re =` (3477)1/3 = 15.15

Here is a depiction of their relative sizes.

The particle shown in orange is the tauon, the one in purple is the muonand the one in blue is the electron.

The Neutrino of an Electron

For a long time it was thought that neutrinos have zero mass but a recent study estimated the rest mass energy of a neutrino to be 0.06 of one electron volt. The rest mass energy of anelectron is about 0.511 million electron volts. With this ratio of masses and equal mass densitythe radius of a neutrino would be about 1/2000 of that of an electron.

Here is a depiction of their relative sizes.

The electron is the large blue sphere and its neutrino is the near pinpoint green sphere to its left.

The Proton and the π Meson

In 1934 the Japanese physicist Hideki Yukawa published an article that predicted the existence of aparticle intermediate in mass between the electron and the proton. Its mass was to be roughly 200 times themass of an electron. When later a particle was found in cosmic ray debris with a mass 207 times that of an electronthe physics community thought Yukawa had been amazingly accurate. But that particle did not have the physical attributesYukawa predicted. That particle turned out to be a heavy electron now called a muon .

Still later a particle was found with a mass about 270 times that of an electron that had the right attributes.More precisely its mass was 273 times that of an electron. It subsequenty came to called a positive π meson.There also are a negative π meson and a neutral π meson.

A proton has a mass 1836 times that of an electron. Therefore the ratio of the radius of a π+ meson to that of a proton is given by

Rπ/Rp = (273/1836)1/3 = (0.1487)1/3 = 0.53

Here is a visual depiction of their relative sizes.

with the π meson shown in yellow.

Quarks

The conventional theory asserts that quarks are point particles. But there is no getting around the fact thatit would take an infinite amount of energy to create even one charged point particle. Thus there is not enoughenergy in the entire Universe, even if all of its mass were converted into energy, to create even one charged point particle. And there are zillions upon zillions of quarks in the Universe. Further more if one charged pointparticle did exist it could explode releasing more energy than in all the stars of the Universe.

Consider a charge which exerts a force inversely proportional to separation distance squared. There is a wonderful theorem in mathematical physics which says that a spherically distributed charge of thattype affects other charged bodies outside of itself as if all of its charge were concentrated at its center. Thus any evidence for a pointparticle is evidence for a spherically distributed charged particle.

For a particle located within a charged spherical shell there is no force exerted.

Nucleons (protons and neutrons) are composed of three concentric shells of quarks.

A Proton

A Neutron

For further details on the Concentric Spheres Model of Nucleon Structuresee Quarkic Structure of Nucleons.

The outer surface of a neutron would be the outer surface of a large Down quark.Similarly the outer surface of a proton would be the outer surface of a large Up quark.Thus here is what a Down quark and an Up quark would look like.

The Down quark is on the left.

Mass Density of the Proton

The volume V of a proton is

V = (4/3)π(0.8768)³ = 2.8235 cubic fermi

The mass of a proton is 1.6726216x10−27 kg,which is the same as 1.6726216 octillionth of a gram.Thus the mass density of a proton is 0.5924 octillionth of a gram per cubic fermiwhich is the same as 5.924x1017 kg/m³.

At this density a sphere of radius 0.5 millimeter, the size of a BB, would have a massof 7.405x107 kg or about 74 million kilograms.

(To be continued.)

Nuclear Binding Energy and the Mass Defect

A neutron has a slightly larger mass than the proton. These are often given in terms of an atomic mass unit, where one atomic mass unit (u) is defined as 1/12th the mass of a carbon-12 atom.

ParticleMass (kg) Mass (u) Mass (Mev/c2)
1 atomic mass unit 1.660540 x 10-27 kg 1.000 u 931.5 MeV/c2
neutron 1.674929 x 10-27 kg 1.008664 u 939.57 MeV/c2
proton 1.672623 x 10-27 kg 1.007276 u 938.28 MeV/c2
electron 9.109390 x 10-31 kg 0.00054858 u 0.511 MeV/c2

Einstein's famous equation relates energy and mass:

E = mc2

Mass of neutron in kilogram

You can use that to prove that a mass of 1 u is equivalent to an energy of 931.5 MeV.

Something should strike you as strange about the table above. The carbon-12 atom has a mass of 12.000 u, and yet it contains 12 objects (6 protons and 6 neutrons) that each have a mass greater than 1.000 u, not to mention a small contribution from the 6 electrons.

This is true for all nuclei, that the mass of the nucleus is a little less than the mass of the individual neutrons, protons, and electrons. This missing mass is known as the mass defect, and represents the binding energy of the nucleus.

The binding energy is the energy you would need to put in to split the nucleus into individual protons and neutrons. To find the binding energy, add the masses of the individual protons, neutrons, and electrons, subtract the mass of the atom, and convert that mass difference to energy. For carbon-12 this gives:

Mass Of Neutron In Kg

Mass defect = Dm = 6 * 1.008664 u + 6 * 1.007276 u + 6 * 0.00054858 u - 12.000 u = 0.098931 u

Mass Of A Neutron Star In Kg

The binding energy in the carbon-12 atom is therefore 0.098931 u * 931.5 MeV/u = 92.15 MeV.

Mass To Kilogram

In a typical nucleus the binding energy is measured in MeV, considerably larger than the few eV associated with the binding energy of electrons in the atom. Nuclear reactions involve changes in the nuclear binding energy, which is why nuclear reactions give you much more energy than chemical reactions; those involve changes in electron binding energies.