Question:
A certain nucleus undergoes two successive decays, as shown in the decay chain below:
Given that the mass of the parent nucleus X
is 100 amu and that of the daughter nucleus Y
is 94 amu, determine the energy released in the first decay process, assuming the daughter nucleus Y
is in its ground state.
(Assume the speed of light, c
, is approximately 3.0 x 10^8 m/s)
Answer:
Let's assume that the decay process from parent nucleus X
to daughter nucleus Y
is an alpha decay, where an alpha particle (^4He
) is emitted. In alpha decay, the nucleus X
loses 2 protons and 2 neutrons. This means that the mass of the emitted alpha particle (m_alpha
) is equal to 4 amu.
Given:
X
(m_parent) = 100 amuY
(m_daughter) = 94 amuWe can calculate the mass lost during the decay process using the equation:
Δm = m_parent - m_daughter - m_alpha
Substituting the given values, we have:
Δm = 100 amu - 94 amu - 4 amu
Δm = 2 amu
The energy released during the decay process can be calculated using Einstein's mass-energy equivalence equation:
E = Δm c^2
Substituting the values:
E = 2 amu * (3.0 x 10^8 m/s)^2
E ≈ 1.797 x 10^18 J
Hence, the energy released in the first decay process is approximately 1.797 x 10^18 J
.