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Nuclei Test - 1...

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  • Question 1
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    41H1 2He4+2e+ + 26MeV4_{1}H^{1} \rightarrow  _{2}He^{4}+2e^{+}  + 26 MeV
    The above reaction represents 

  • Question 2
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    The β\beta-decay process, discovered around 1900, is basically the decay of a neutron (n)(n). In the laboratory, a proton (p)(p) and an electron (e)(e^{-}) are observed as the decay products of the neutron. Therefore, considering the decay of a neutron as a two-body decay process, it was predicted theoretically that the kinetic energy of the electron should be a constant. But experimentally, it was observed that the electron kinetic energy has a continuous spectrum. Considering a three-body decay process, i.e. np+e+ven\rightarrow p+e^{-}+\overline{v}_{e}, around 1930, Pauli explained the observed electron energy spectrum. Assuming the anti-neutrino (ve)(\overline{v}_{e}) to be massless and possessing negligible energy, and the neutron to be at rest, momentum and energy conservation principles are applied. From this calculation, the maximum kinetic energy of the electron is 0.8×106eV0.8\times 10^{6}eV. The kinetic energy carried by the proton is only the recoil energy.
    If the anti-neutrino had a mass of 3 eV/c2eV/c^{2} (where cc is the speed of light) instead of zero mass, what should be the range of the kinetic energy, KK, of the electron?

  • Question 3
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    Directions For Questions


    Scientists are working hard to develop nuclear fusion reactor. Nuclei of heavy hydrogen, 12H^{2}_{1}\mathrm{H} known as deuteron and denoted by D\mathrm{D} can be thought of as a candidate for fusion reactor. The DD\mathrm{D}-\mathrm{D} reaction is 12H+12H23He+n+^{2}_{1}\mathrm{H}+_{1}^{2}\mathrm{H}\rightarrow_{2}^{3} He +\mathrm{n}+ energy. In the core of fusion reactor, a gas of heavy hydrogen is fully ionized into deuteron nuclei and electrons. This collection of  12H^{2}_{1}\mathrm{H} nuclei and electrons is known as plasma. The nuclei move randomly in the reactor core and occasionally come close enough for nuclear fusion to take place. Usually, the temperatures in the reactor core are too high and no material wall can be used to confine the plasma. Special techniques are used which confine the plasma for a time t0t_{0} before the particles fly away from the core. If n is the density (number/volume) of deuterons, the product nt0nt_{0} is called Lawson number. In one of the criteria, a reactor is termed successful if Lawson number is greater than 5×1014 s/cm35 \times 10^{14} s/cm^{3}.
    It may be helpful to use the following: Boltzmann constant k=8.6×105eV/K; e24πϵ0 =1.44×109eVmk=8.6 \times 10^{-5} eV/K; \displaystyle \frac{\mathrm{e}^{2}}{4\pi\epsilon_{0}} =1.44\times 10^{9}\mathrm{e}\mathrm{V}\mathrm{m}.

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    In the core of nuclear fusion reactor, the gas becomes plasma because of

  • Question 4
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    Directions For Questions


    Scientists are working hard to develop nuclear fusion reactor. Nuclei of heavy hydrogen, 12H^{2}_{1}\mathrm{H} known as deuteron and denoted by D\mathrm{D} can be thought of as a candidate for fusion reactor. The DD\mathrm{D}-\mathrm{D} reaction is 12H+12H23He+n+^{2}_{1}\mathrm{H}+_{1}^{2}\mathrm{H}\rightarrow_{2}^{3} He +\mathrm{n}+ energy. In the core of fusion reactor, a gas of heavy hydrogen is fully ionized into deuteron nuclei and electrons. This collection of  12H^{2}_{1}\mathrm{H} nuclei and electrons is known as plasma. The nuclei move randomly in the reactor core and occasionally come close enough for nuclear fusion to take place. Usually, the temperatures in the reactor core are too high and no material wall can be used to confine the plasma. Special techniques are used which confine the plasma for a time t0t_{0} before the particles fly away from the core. If n is the density (number/volume) of deuterons, the product nt0nt_{0} is called Lawson number. In one of the criteria, a reactor is termed successful if Lawson number is greater than 5×1014 s/cm35 \times 10^{14} s/cm^{3}.
    It may be helpful to use the following: Boltzmann constant k=8.6×105eV/K; e24πϵ0 =1.44×109eVmk=8.6 \times 10^{-5} eV/K; \displaystyle \frac{\mathrm{e}^{2}}{4\pi\epsilon_{0}} =1.44\times 10^{9}\mathrm{e}\mathrm{V}\mathrm{m}.

    ...view full instructions

    Assume that two deuteron nuclei in the core of fusion reactor at temperature T are moving towards each other, each with kinetic energy 1.5kT1.5 kT, when the separation between them is large enough to neglect Coulomb potential energy. Also neglect any interaction from other particles in the core. The minimum temperature TT required for them to reach a separation of 4×10154 \times 10^{-15} m is in the range

  • Question 5
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    The nucleus finally formed in fusion of protons in proton-proton cycle is that of :

  • Question 6
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    Directions For Questions

    The mass of nucleus ZAX^{A}_{Z}X is less than the sum of the masses of (AZ\mathrm{A}-\mathrm{Z}) number of neutrons and Z\mathrm{Z} number of protons in the nucleus. The energy equivalent to the corresponding mass difference is known as the binding energy of the nucleus. A\mathrm{A} heavy nucleus of mass M\mathrm{M} can break into two light nuclei of mass m1\mathrm{m}_{1} and m2\mathrm{m}_{2} only if (m1+m2)<M.(\mathrm{m}_{1}+\mathrm{m}_{2})<\mathrm{M}. Also two light nuclei of masses m3\mathrm{m}_{3} and m4\mathrm{m}_{4} can undergo complete fusion and form a heavy nucleus of mass M\mathrm{M}' only if (m3+m4)>M(\mathrm{m}_{3} +\mathrm{m}_{4})>\mathrm{M}'. The masses of some neutral atoms are given in the table above:

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    The kinetic energy (in keV) of the alpha particle, when the nucleus 84210Po^{210}_{84}Po at rest undergoes alpha decay, is

  • Question 7
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    The source of stellar energy is 

  • Question 8
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    After losing two electrons, an atom of Helium becomes equivalent to

  • Question 9
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    In the options given below, let EE denote the rest mass energy of a nucleus and n 'n\ ' a neutron. The correct option is 

  • Question 10
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    A nucleus with mass number 220220 initially at rest emits an α\alpha-particle. lf the Q\mathrm{Q} value of the reaction is 5.55.5 MeV\mathrm{M}\mathrm{e}\mathrm{V}, calculate the kinetic energy of the α\alpha-particle.

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