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Re: Nuclear topics in physics?



I goofed. E & L is not that complete. They have integrated nuclear
energy (á la Ludwik) into the Relativistic Mechanics Ch. by discussing
pion decay, fission, chemical reactions, and nuclear reaction Q values.
They do not discuss other decays. They do explain why U-235 (actually
236) will fission as the result of the energy from a thermal neutron
while U-238 (239) requires a "fast' neutron. I expect why the barriers
are different (quantitative) is grad. level. It was from this text,
long after matriculating, that I learned that chemical energy and
nuclear energy have the same source, and why they differ by ~ 5 E+7.

bc

"John S. Denker" wrote:

Ludwik suggested asking:
(1) What happens to the released energy? (2) What
prevents heavy nuclei from fissioning very rapidly?


Bernard Cleyet wrote:

Eisberg and Lerner discuss this, I think well, in one page.

OK, I'll take the bait. I don't have that book.

I still think the original question (2) sounds a bit backwards. The
really heavy nuclei _do_ decay very rapidly.

So I think the questions should be
2a) why don't light nuclei decay?
2b) why don't heavy nuclei decay any more rapidly than they do?
2c) why is spontaneous fission rare compared to other decay modes?

I don't see any way to even approach question (2c) without first
spending some quality time running down the various decay modes.

http://www.science.uwaterloo.ca/~cchieh/cact/nuctek/decaytype.html