Alpha Decay Energy (Q-value)
The energy released in alpha decay equals the mass difference times c². A positive Q-value means the decay is energetically allowed.
Variables
Derivation
Conservation of energy and mass-energy equivalence.
Your notes
Constants in this formula
Other modern physics formulas with the same quantities
- Lorentz Factor (Special Relativity) shares Speed of light
- Time Dilation (Special Relativity) shares Speed of light
- Length Contraction (Special Relativity) shares Speed of light
- Relativistic Momentum (Special Relativity) shares Speed of light
- Relativistic Total Energy (Special Relativity) shares Speed of light
- Relativistic Kinetic Energy (Special Relativity) shares Speed of light
Where this formula is listed
- Modern Physics formulas, under Nuclear Physics, alongside Radioactive Decay Law, Half-Life, Activity, Beta Decay and Nuclear Radius.
- In the modern physics list it comes after Nuclear Binding Energy and before Beta Decay.
- Modern Physics formula sheet, one of 41 formulas printed with symbol keys and SI units.
- The full formula index, grouped by category and topic.
Common questions
What is the Alpha Decay Energy (Q-value) formula?
Alpha Decay Energy (Q-value) is written Q = (m_parent − m_daughter − m_α)c². The energy released in alpha decay equals the mass difference times c². A positive Q-value means the decay is energetically allowed. It belongs to Modern Physics, under Nuclear Physics.
What are the units in Q = (m_parent − m_daughter − m_α)c²?
In SI units, Q is energy released (q-value), measured in J; m_parent is parent nucleus mass, measured in kg; m_daughter is daughter nucleus mass, measured in kg; m_α is alpha particle mass, measured in kg; c is speed of light, measured in m/s.
How is the Alpha Decay Energy (Q-value) formula derived?
Conservation of energy and mass-energy equivalence. The result is Q = (m_parent − m_daughter − m_α)c².