Class 12

Physics

Modern Physics

Nuclei

Which among the three causes the least biological damage externally?

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Carbon $14$ dating is used to estimate the age of an archeological specimen.

In a periodic table the average atomic mass of magnesium is given as 24.312 u. The average value is based on their relative natural abundance on earth. The three isotopes and their masses are $_{12}Mg$ (23.98504u), $_{12}Mg$ (24.98584u) and $_{12}Mg$ (25.98259u). The natural abundance of $_{12}Mg$ is 78.99% by mass. Calculate the abundances of other two isotopes.

Obtain the binding energy of the nuclei $_{26}Fe$ and $_{83}Bi$ in units of MeV from the following data:(a) $m(_{26}Fe)=55.934939u$(b) $m(_{83}Bi)=208.980388u$

Consider the DT reaction (deuteriumtritium fusion).$_{1}H+_{1}H→_{2}He+n$(a) Calculate the energy released in MeV in this reaction from the data: $m(_{1}H)=2.014102u$ $m(_{1}H) =3.016049u$(b) Consider the radius of both deuterium and tritium to be approximately 2.0 fm. What is the kinetic energy needed to overcome the coulomb repulsion between the two nuclei? To what temperature must the gas be heated to initiate the reaction? (Hint: Kinetic energy required for one fusion event =average thermal kinetic energy available with the interacting particles = 2(3kT/2); k = Boltzmans constant, T = absolute temperature.)

The rest mass of an electron as well so that of positron is $0.51cMeV$. When an electron and positron are annihilate they produce gamma-rays of wavelength(s)

Calculate the height of the potential barrier for a head on collision of two deuterons.

Why does the radiation C deflect more than A?

The fission properties of $_{94}Pu$ are very similar to those of $_{92}U$. The average energy released per fission is 180 MeV. How much energy, in MeV, is released if all the atoms in 1 kg of pure $_{94}Pu$ undergo fission?