
#1
Nov2313, 08:17 AM

P: 41

In high school, we calculated the reactionenergy by equating the mass difference and the energy difference with proportionality factor cē.
How does Einstein's theory of relativity suddenly enter nuclear physics? It startles me because both fields developped historically completely divergent. Aren't there nuclear physical ways to calculate this energy? In retrospect, the calculations seem too simple to be true. 



#2
Nov2313, 08:52 AM

P: 1,291

The theory of relativity is a universal theory. It applies to all of physics, including nuclear physics.
Sometimes calculations are both simple and true. 



#3
Nov2313, 09:21 AM

P: 41

So is quantum mechanics...




#4
Nov2313, 09:37 AM

P: 1,291

Nuclear reactions and Einstein's famous formula
Quantum mechanics is... (Half an answer to half a question)




#5
Nov2313, 09:44 AM

P: 41

My knowledge is too incomplete to ask full questions. But as far as I know, quantum mechanics relates the same variables but is not consistent with general relativity and hence might provide a different answer.




#6
Nov2313, 09:49 AM

P: 1,291

General relativity is a theory of gravity which plays no role in nuclear physics. Relativity on the other hand is a universal metatheory that applies to all physics including nuclear physics.




#7
Nov2313, 10:16 AM

P: 41

I see, special relativity isn't a special case of general relativity.




#8
Nov2313, 10:33 AM

Sci Advisor
Thanks
P: 2,973

1) Special relativity applies in the special case of flat spacetime, whereas general relativity applies in the general case of flat or curved spacetime. 2) Although special relativity is therefore a special case of general relativity, there are a large number of problems, including just about everything at and below atomic scale, for which we don't use general relativity. That's not because it's not applicable (it is the more general theory, after all), it's because the general relativistic effects are so insignificant that we can safely ignore them. 3) SR calculations are so much simpler than GR calculations that no one ever uses GR except when it's needed. 



#9
Nov2313, 12:56 PM

P: 1,291





#10
Nov2313, 01:29 PM

Sci Advisor
HW Helper
P: 1,937

E=mc^2 holds for any process, it is just large enough in nuclear processes to be seen. When hydrogen burns, the mass of H_2O is less than the mass of H_2 and O, but this difference is too small to be seen. 



#11
Nov2313, 05:59 PM

P: 41

Is the binding energy a measure of the internal motion in the nucleus?




#12
Nov2313, 08:25 PM

PF Gold
P: 11,058




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