13.29 Obtain the maximum kinetic energy of β-particles, and the radiation frequencies of γ-decays in the decay scheme shown in Fig. 13.6. You are given that:

m(198Au) = 197.968233 u

m(198Hg) = 197.966760 u

Figure13.6

Hint: The maximum kinetic energy of β-particles is the maximum difference in the energy levels.
Step 1: Find the radiation frequencies of
γ1-decay.
It can be observed from the given y-decay diagram that γ1-decay from the 1.088 MeV
energy level to the 0 MeV energy level.
Hence, the energy corresponding to γ1-decay is given as:
\(E_{1}=1.088-0=1.088 \quad \mathrm{MeV}\\ h \nu_{1}=1.088 \times 1.6 \times 10^{-19} \times 10^{6} \quad \mathrm{~J}\\ where, h= Planck's~constan t=6.6 \times 10^{-34} J s\\ \nu_{1}= \text{Frequency of radiation radiated by} ~\gamma_{1}-decay\\ \therefore \nu_{1}=\frac{E_{1}}{h}=\frac{1.088 \times 1.6 \times 10^{-19} \times 10^{6}}{6.6 \times 10^{-34}}=2.637 \times 10^{20} \mathrm{~Hz} \)
Step 2: Find the radiation frequencies of γ2-decay.
It can be observed from the given y-decay diagram that y2 decays from the 0.412 MeY energy level to the 0 MeV energy level.
Hence, the energy corresponding to y2-decay is given as:
\(E_{2}=0.412-0=0.412 \quad \mathrm{MeV}\\ h \nu_{2}=0.412 \times 1.6 \times 10^{-19} \times 10^{6} \mathrm{~J}\\ where, \nu_{2}= \text{Frequency of radiation radiated by}~\gamma_{2}-decay\\ \therefore \nu_{2}=\frac{E_{2}}{h}=\frac{0.412 \times 1.6 \times 10^{-19} \times 10^{6}}{6.6 \times 10^{-34}}=9.988 \times 10^{19} \mathrm{~Hz}\)
Step 3: Find the radiation frequencies of γ3-decay.
It can be observed from the given y-decay diagram that y3 decays from the 1.088 MeV energy level to the 0.412 MeV energy level.
Hence, the energy corresponding to y3-decay is given as:
\(E_{3}=1.088-0.412=0.676 \mathrm{MeV}\\ h\nu_{3}=0.676 \times 10^{-19} \times 10^{6} J\\ where, v_{3}=\text{ Frequency of radiation radiated by}~\gamma_{3}-decay\\ \therefore \nu_{3}=\frac{E_{3}}{h}=\frac{0.676 \times 1.6 \times 10^{-19} \times 10^{6}}{6.6 \times 10^{-34}}=1.639 \times 10^{20} \quad \mathrm{Hz}\)
Step 4: Find the maximum kinetic energy of β--particles.

Mass of mA78198u=197.968233 u
Mass of mH80198g=197.966760 u
1 u=931.5 MeV/c2
Energy of the highest level is given as:
E=mA78198u-mH80190g
=197.968233-197.966760=0.001473 u
=0.001473×931.5=1.3720995 MeV
β1 decays from the 1.3720995 MeV level to the 1.088 MeV level
Maximum kinetic energy of the β1 particle=1.3720995-1.088=0.2840995 MeV
β2 decays from the 1.3720995 MeV level to the 0.412 MeV level
Maximum kinetic energy of the β2 particle =1.3720995-0.412=0.9600995 MeV