Page 17 - GALIET PHYSICS BLOSSOMS IV+

o It causes radioactivity.
o Nuclear power plants depend on nuclear fission of uranium or plutonium, while the Sun relies on nuclear fusion, the combining of smaller nuclei
into a large nucleus, to turn hydrogen into helium.
• Nuclear Fission is an example of quantum tunneling (QT), and QT is an example of microchips, radioactive decay, and astrophysics’ processes. • QT:
o Occurs when electrons or other particles cross through wall-like barriers.
o To cross these electromagnetic repulsion barriers, the particle needs to gain some excess energy.8 o But there is uncertainty in energy (Heisenberg).
§ At a particular time, it is possible for an electron to have more energy than expected, allowing it to cross the barrier. § To do so, the particle borrows excess energy during QT, but it must pay it back right away!
§ As a result, uncertainty in energy causes quantum tunneling.
o Other Quantum “uncertainty” considerations too:
• Because the position of the particle is uncertain, it can be on the barrier’s other side!
• Because the particle’s momentum is uncertain, it can have enough momentum to cross over the barrier!
o Allows alphas to escape even when the nuclear force overpowers their energy to do so. Matter in the form of a wave allows the alpha particle to spend part of its time far away from the nucleus where the repulsive EM force fully compensates for the nuclear force’s attraction.
§ Cause of Alpha Decay
• When the alpha particle and the nucleus, both positively charged, repel each other according to Coulomb’s law. However, the
8 462. http://library.thinkquest.org/17940/texts/fission/fission.html
nuclear force keeps it in check.
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