Nuclear reactions

Содержание и основные понятия

The nuclear reaction changes the composition of the kernels, and the energy difference is expressed as the generation or absorption of energy; a small mass defect corresponds to a large energy.
GEF · Grade 9
PIF · Baseline
Interactive model
Communications energy
defect in mass
division
synthesis
chain reaction
01
The physical picture
What happens and what boundaries the model has.
Main message
The nuclear reaction changes the composition of the kernels, and the energy difference is expressed as the generation or absorption of energy; a small mass defect corresponds to a large energy.
The reaction equations retain the electrical charge and number of nucleons.
Heavy core separation can support chain reaction.
The lung synthesis feeds the stars, but on Earth it requires very high plasma temperatures.
How to reason
First, name the system and the interaction, then select the values, and only then write down the law. The formula works within the model's assumptions.
02
Laws and values
Symbols should be read as a relationship of values, not as a recipe for substitution.
E
=
Δ
m
c
2
E=\Delta m\,c^2
E
=
Δ
m
c
2
Power of mass defect
∑
Z
до
=
∑
Z
после
,
∑
A
до
=
∑
A
после
\sum Z_{\text{до}}=\sum Z_{\text{после}},\quad \sum A_{\text{до}}=\sum A_{\text{после}}
∑
Z
up to
​
=
∑
Z
after
​
,
∑
A
up to
​
=
∑
A
after
​
response balance
Review of the situation
The loss of weight of only 1 mg corresponds to the energy of about 9:1010 J if the mass is completely converted to energy.
04
Links and application
In the real world
The loss of weight of only 1 mg corresponds to the energy of about 9:1010 J if the mass is completely converted to energy.
Model verification
Compare the prediction with observation, evaluate the units, the order of magnitude and the influence of the factors not taken into account. Disparity does not always mean an error of law: often idealization is no longer sufficient.
C
What needs to be understood
Outcome 1
Explain the physical meaning of the topic "Nuclear Reactions" through a model, not just a formula.
Outcome 2
Distinguish and correctly use terms: power of communication, fault of mass, division.
Outcome 3
Indicate the conditions for the applicability of the law, verify units and limit cases.
T
Terms of the topic
The definition should indicate the physical meaning, not a substitute for a domestic synonym.
Communications energy
The energy needed to fully separate the connected system into free parts.
defect in mass
The difference between the sum of the free masses and the mass of the connected system.
division
Nuclear reaction of the heavy core to lighter fragments with energy and neutrons.
synthesis
The nuclear reaction of combining the lungs into a heavier one with a possible release of energy.
chain reaction
A self-sustaining process of division in which the products of the previous act trigger subsequent acts.
F
Origin and conclusion of the formulas
The fundamental law cannot be "proven" by algebras: for each record, it is stated whether it is a definition, an experimental law, or a model effect.
E
=
Δ
m
c
2
E=\Delta m\,c^2
E
=
Δ
m
c
2
model effect
Power's a mass defect.
The following is an indication of the definition, experience or law from which this entry arises and where it is applicable.
Δ
m
=
Z
m
p
+
N
m
n
−
m
ядра
\Delta m=Zm_p+Nm_n-m_{\text{ядра}}
Δ
m
=
Z
m
p
​
+
N
m
n
​
−
m
of kernels
​
The mass defect is found to be the difference between the sum of the free nuclone masses and the mass of the attached kernel.
E
0
=
m
c
2
E_0=mc^2
E
0
​
=
m
c
2
The relativist model binds the mass of the rest of the system to the corresponding energy of the peace.
E
св
=
(
m
свобод
−
m
ядра
)
c
2
=
Δ
m
c
2
E_{\text{св}}=(m_{\text{свобод}}-m_{\text{ядра}})c^2=\Delta m\,c^2
E
Sv
​
=
(
m
freedoms
​
−
m
of kernels
​
)
c
2
=
Δ
m
c
2
The difference between the energy of the rest of the free and connected nucleons is equal to that of the core.
Conditions:
Mass defect and energy refer to the same initial and final states; the mass of rest is expressed in harmony; c is the speed of light in the vacuum.
Monitoring:
The dimensions of both parts shall coincide; the result shall be checked for sign, order and limit case.
∑
Z
до
=
∑
Z
после
,
∑
A
до
=
∑
A
после
\sum Z_{\text{до}}=\sum Z_{\text{после}},\quad \sum A_{\text{до}}=\sum A_{\text{после}}
∑
Z
up to
​
=
∑
Z
after
​
,
∑
A
up to
​
=
∑
A
after
​
empirical law
Response balance.
The following is an indication of the definition, experience or law from which this entry arises and where it is applicable.
Q
до
=
e
∑
Z
до
,
Q
после
=
e
∑
Z
после
Q_{\text{до}}=e\sum Z_{\text{до}},\quad Q_{\text{после}}=e\sum Z_{\text{после}}
Q
up to
​
=
e
∑
Z
up to
​
,
Q
after
​
=
e
∑
Z
after
​
Maintaining the electrical charge requires equality of the total charge numbers of the reaction participants.
N
нуклонов,до
=
∑
A
до
,
N
нуклонов,после
=
∑
A
после
N_{\text{нуклонов,до}}=\sum A_{\text{до}},\quad N_{\text{нуклонов,после}}=\sum A_{\text{после}}
N
Noklons
,
up to
​
=
∑
A
up to
​
,
N
Noklons
,
after
​
=
∑
A
after
​
The school record of nuclear reactions maintains the total number of nucleons and therefore balances the mass numbers.
∑
Z
до
=
∑
Z
после
,
∑
A
до
=
∑
A
после
\sum Z_{\text{до}}=\sum Z_{\text{после}},\quad \sum A_{\text{до}}=\sum A_{\text{после}}
∑
Z
up to
​
=
∑
Z
after
​
,
∑
A
up to
​
=
∑
A
after
​
Both regulations express experimentally established conservation laws and provide an unknown response product.
Conditions:
Nuclear reaction in the school nuclide record; all kernels and baked nuclees are included, and for β-delays, charge-bearing particles are also taken into account.
Monitoring:
The dimensions of both parts shall coincide; the result shall be checked for sign, order and limit case.
!
Model boundaries and typical errors
Error: Forget model condition
You can't move the formula to any situation just because it's a coincidence of letters. The key condition of this subject is that the reaction equations retain the electrical charge and the number of nuclons.
How to Check the Mind
Heavy core separation can support chain reaction. Then check the units, vector direction, and result behaviour at zero or very large parameter.
Σ
Conclusion on the topic
Nuclear reactions
The nuclear reaction changes the composition of the kernels, and the energy difference is expressed as the generation or absorption of energy; a small mass defect corresponds to a large energy.
The reaction equations retain the electrical charge and number of nucleons.
Heavy core separation can support chain reaction.
Any numerical result shall be accompanied by a unit, a sign and an explanation of its physical meaning.
The content is consistent with the FRP on Physics of the OS/OSS 2025 and the subject matter of the current lines of the PNP: I. M. Peryškin and co-authors (7–9), G. J. Mäkishev and coauthors (10–11), and with the lines "Engineers of the Future" and V. A. Kasyanov. The original texts are not reproduced, the text of the textbooks is not reproduced.