Sunday, April 17, 2016

[dmuwqriz] Keep the protons together

Compute the strength of the electromagnetic repulsive force between protons in the atomic nucleus, probably strength per unit mass, and realize just how powerful the strong nuclear force is.  The strong nuclear force does not merely balance electromagnetic repulsion of protons: for small nuclei it's very hard to induce fission or radioactive decay by perturbing them with particle collisions.  (Larger nuclei are another matter, often easily willing to give up positive charges by alpha or positron emission.)  Similarly, it's amazing that small nuclei get more stable (so release energy) by stuffing more protons into a small region through fusion.

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