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We can distinguish three different realms of matter, three levels on the quantum(量子的) ladder. The first is the atomic realm which includes the world of atoms, their interactions and the structures that are formed by them. Such as molecules, liquids and solids, and gases and plasmas. This realm includes all the phenomena of atomic physics, chemistry, and in a certain sense biology. The energy exchanges taking place in this realm are of a relatively low over. If these exchanges are below one electron volt, such as in the collisions between molecules of the air in a room, then atoms and molecules can be regarded as elementary particles. That is, they have “conditional elementarily” because they keep their identity and do not change in any collisions or in other processes at these low energy exchanges. If one goes to higher energy exchanges, say 104 electron volts then atoms and molecules will decompose into nuclear and electrons; at this level, the latter particles must be considered as elementary. We find examples of structures and processes of this first rung of the quantum ladder on Earth, on planets, and on the surfaces of stars.
The next rung(阶梯) is the nuclear realm. Here the energy exchanges are much higher, on the order of millions of electron volts. As long as we are dealing with phenomena in the atomic realm such amounts of energy are unavailable and most nuclei are inert: they do not change. However, if one applies energies of millions of electron volts, nuclear reactions, fission and fusion, and the processes of radioactivity occur, our elementary particles then are protons neutrons and electrons. In addition, nuclear processes produce neutrinos, particles that have no detectable mass or charge. In the universe, energies at this level are available in the centers of stars and in star explosions. Indeed, the energy radiated by the stars is produced by nuclear reactions. The natural radioactivity we find on Earth is the longlived remnant of the time when nowearthly matter was expelled into space by a major stellar explosion.
The third rung of the quantum ladder is the sub nuclear realm. Here we are dealing with energy exchanges of many billions of electron volts. We encounter excited nucleons, new types of particles such as mesons, heavy electrons, quarks and glens, and also antimatter in large quantities. The gluons are the quanta, or smallest units, of the force (the strong force) that keeps the quarks together. As long as we are dealing with the atomic or nuclear realm, these new types of particles do not occur and the nucleons remain inert. But at sub nuclear energy levels, the nucleons and mesons appear to be composed of quarks, so that the quarks and gluons figure as elementary particles.
26. According to the passage, which of the following can be found in the atomic realm?
\[A\] More than one level of energy exchange.
\[B\] Exactly one elementary particle.
\[C\] Exactly three kinds of atomic structure.
\[D\] Three levels in the quantum ladder.
27. The level of energy can be expected on information in the passage that there would probably be
\[A\] excited nucleons
\[B\] elementary mesons
\[C\] another set of elementary particles
\[D\] a kind of particle without detectable mass or change
28. According to the passage, radioactivity that occurs naturally on Earth is the result of.
\[A\] the production of particles that have no detectable mass or electric change
\[B\] high energy exchanges on the nuclear level that occurred in an ancient explosion in a star
\[C\] processes that occur in the center of the Sun which emits radiation to the Earth
\[D\] phenomena in the atomic realm hat cause atoms and molecules to decompose into nuclei and electrons
29. The passage speaks of particles as having conditional elementarily if they.
\[A\] remain unchanged at a given level of energy exchange
\[B\] cannot be decomposed into smaller constituents
\[C\] are mathematically simpler than some other set of particles
\[D\] release energy at a low level in collisions
30. The best title of the passage is .
\[A\] The Interaction of the Realms on the Quantum Ladder
\[B\] Atomic Structures Found on Earth, on Other Planets, and on the Surfaces of Stars
\[C\] Levels of Energy that are Released in Nuclear Reactions on Earth and in Stars
\[D\] Particles and Processes Found in the Atom
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