Einstein's mass–energy equivalence principle
Jentschel, Michael Nuclear and Particle Physics Group, Institut Laue-Langevin, Grenoble, France.
- Basis of a direct test
- Measurement of relative atomic masses
- Measurement of gamma-ray frequencies
- Experiments and results
- Links to Primary Literature
Einstein's mass–energy equivalence principle, E = mc2, where E is energy, m is mass, and c is the speed of light, is probably the best-known formula in science. Despite its algebraic simplicity, however, it demonstrates an inherent fundamental difficulty for direct experimental verification: The comparison between energy and mass is realized by a factor of c2, which magnifies any mass variation by 17 orders of magnitude. Accordingly, the energy equivalent of 1 kg (2.2 lb) of mass is comparable to the energy released by the largest nuclear explosion achieved so far. Therefore, the choice of physical system for experimental verification of Einstein's formula is limited to microscopic masses. Here the thermal neutron capture reaction appears to be the best candidate: A thermal neutron with a kinetic energy of a few millielectronvolts (meV) induces a nuclear reaction in which a new isotope with excitation energy of the order of 10 MeV is formed. The relative energy uncertainty of this reaction is therefore of the order of 10−9, which would allow carrying out very precise experiments.
The content above is only an excerpt.
for your institution. Subscribe
To learn more about subscribing to AccessScience, or to request a no-risk trial of this award-winning scientific reference for your institution, fill in your information and a member of our Sales Team will contact you as soon as possible.
to your librarian. Recommend
Let your librarian know about the award-winning gateway to the most trustworthy and accurate scientific information.
AccessScience provides the most accurate and trustworthy scientific information available.
Recognized as an award-winning gateway to scientific knowledge, AccessScience is an amazing online resource that contains high-quality reference material written specifically for students. Its dedicated editorial team is led by Sagan Award winner John Rennie. Contributors include more than 9000 highly qualified scientists and 39 Nobel Prize winners.
MORE THAN 8500 articles and Research Reviews covering all major scientific disciplines and encompassing the McGraw-Hill Encyclopedia of Science & Technology and McGraw-Hill Yearbook of Science & Technology
115,000-PLUS definitions from the McGraw-Hill Dictionary of Scientific and Technical Terms
3000 biographies of notable scientific figures
MORE THAN 17,000 downloadable images and animations illustrating key topics
ENGAGING VIDEOS highlighting the life and work of award-winning scientists
SUGGESTIONS FOR FURTHER STUDY and additional readings to guide students to deeper understanding and research
LINKS TO CITABLE LITERATURE help students expand their knowledge using primary sources of information