write a short note on the DISCOVERY OF NEUTRONS.
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Discovery of the Neutron
It is remarkable that the neutron was not discovered until 1932 when James Chadwick used scattering data to calculate the mass of this neutral particle. Since the time of Rutherford it had been known that the atomic mass number A of nuclei is a bit more than twice the atomic number Z for most atoms and that essentially all the mass of the atom is concentrated in the relatively tiny nucleus. As of about 1930 it was presumed that the fundamental particles were protons and electrons, but that required that somehow a number of electrons were bound in the nucleus to partially cancel the charge of A protons. But by this time it was known from the uncertainty principle and from "particle-in-a-box" type confinement calculations that there just wasn't enough energy available to contain electrons in the nucleus.A rough scale of the energy required for the confinement of a particle to a given dimension can be obtained by setting the DeBroglie wavelength of the particle equal to that dimension. For example, if we presume that the dimension of a hydrogen atom is about 0.2 nm, then the corresponding confinement energy is about 38 eV, the correct order of magnitude for atomic electrons. But to confine an electron to a nuclear dimension of about 5 fermis requires an energy of about 250 MeV
It is remarkable that the neutron was not discovered until 1932 when James Chadwick used scattering data to calculate the mass of this neutral particle. Since the time of Rutherford it had been known that the atomic mass number A of nuclei is a bit more than twice the atomic number Z for most atoms and that essentially all the mass of the atom is concentrated in the relatively tiny nucleus. As of about 1930 it was presumed that the fundamental particles were protons and electrons, but that required that somehow a number of electrons were bound in the nucleus to partially cancel the charge of A protons. But by this time it was known from the uncertainty principle and from "particle-in-a-box" type confinement calculations that there just wasn't enough energy available to contain electrons in the nucleus.A rough scale of the energy required for the confinement of a particle to a given dimension can be obtained by setting the DeBroglie wavelength of the particle equal to that dimension. For example, if we presume that the dimension of a hydrogen atom is about 0.2 nm, then the corresponding confinement energy is about 38 eV, the correct order of magnitude for atomic electrons. But to confine an electron to a nuclear dimension of about 5 fermis requires an energy of about 250 MeV
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Explanation:
- when it is detected that mass of electron + mass of proton is not equals to mass of atom then chadwick tell that there are some more particles known as neutrons are also present in nucleus
- in 1932 chadwick Discover presence of neutron in nucleus
- neutron are fundamental particle which carry no charge but have mass is equals to Proton mass of neutron is equals to 1.67×10^-27 kg
- why few radioactive fusion reaction chatwi explain presence of neutron which are given in attachment
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