# Conservation of angular momentum in nuclear physics

• burgjeff
In summary, conservation of angular momentum in nuclear physics is a fundamental law stating that the total angular momentum of a closed system remains constant over time, unless an external torque is applied. This applies to nuclear reactions, where the total angular momentum of the reactants must be equal to the total angular momentum of the products. The implications of this law include explaining the stability of atomic nuclei, the behavior of particles in nuclear reactions, and the formation of elements in the universe. It is always conserved in nuclear reactions due to the absence of external torques. Conservation of angular momentum is closely related to other conservation laws, such as conservation of energy and conservation of linear momentum, as they all stem from the principle of conservation of mass and energy.
burgjeff
Say a uranium-238 nucleus with angular momentum II decays to thorium-234 plus an alpha particle. Will the sum of the angular momenta of the thorium-234 nucleus and the alpha particle equal II? What if a photon was emitted during this process, would Ithorium+Iα+hbar=II?

thanks

The relative motion of the nuclei can carry angular momentum, so the result can be different.

To clarify mfb's point, orbital angular momentum must be included when applying angular momentum conservation. But yes, angular momentum is definitely always conserved.

## 1. What is conservation of angular momentum in nuclear physics?

Conservation of angular momentum in nuclear physics is a fundamental law that states that the total angular momentum of a closed system remains constant over time. This means that the total amount of rotational motion in a system will not change unless an external torque is applied.

## 2. How does conservation of angular momentum apply to nuclear reactions?

In nuclear reactions, the total angular momentum of the reactants must be equal to the total angular momentum of the products. This ensures that the laws of conservation of angular momentum are upheld even in the most energetic nuclear reactions.

## 3. What are the implications of conservation of angular momentum in nuclear physics?

The conservation of angular momentum has many important implications in nuclear physics. It helps explain the stability of atomic nuclei, the behavior of particles in nuclear reactions, and the formation of elements in the universe.

## 4. Is conservation of angular momentum always conserved in nuclear physics?

Yes, conservation of angular momentum is a fundamental law of physics that is always conserved in nuclear reactions. This is because there are no external torques acting on a closed system of particles, so the total angular momentum must remain constant.

## 5. How is conservation of angular momentum related to other conservation laws in physics?

The conservation of angular momentum is closely related to other conservation laws, such as conservation of energy and conservation of linear momentum. This is because all of these laws stem from the fundamental principle of conservation of mass and energy, which states that these quantities cannot be created or destroyed, only transformed from one form to another.

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