Lesson 58-61

Translate into Russian paying attention to the Emphatic Constructions:

1. This problem did involve a number of difficulties.

2. It is this problem that involved a number of difficulties.

3. For these students the novelty of the viewpoint adopted does seem, at least, occasionally, to throw familiar concepts into a new relief.

4. It is this contrasting viewpoint that often provides the stimulus for a more critical understanding.

5. This contrasting viewpoint does often provide the stimulus for a more critical understanding.

6. It is this method that yields a time exposure of the nucleus.

7. It is the time exposure of the nucleus that this method yields.

8. This method does yield a time exposure of the nucleus.

9. It is the interpretation of his experiments that led Ampere to believe he had analyzed electromagnetics on sound Newtonian lines.

10. Interpretation of his experiment did lead Ampere to believe he had analyzed electromagnetics on sound Newtonian lines.

III. Catch the meaning of the text and retell it:

Like an atom, a nucleus can exist in a large number of quantum states, Each state corresponds to a different mode of motion of the constituent nucleons, and the various states differ in such properties as energy, angular momentum, parity and size and shape. In talking about size and shape one must therefore specify the state of the nucleus. This is usually done in terms of the energy, which is the easiest property to measure. The ground state, or state of lowest energy, is usually the best known because it is the only one that can be stable, but there is much information to be obtained by raising the energy to an excited level.

Indeed, any experiment that reveals the true shape of a nucleus must necessarily be one that throws the nucleus out of its original energy level. This follows from Heisenberg’s uncertainty relation, ‘ which says that the duration of an

experiment multiplied by the uncertainty in the energy balance is at least equal to Planck’s constant. For a snapshot the duration must be large; in other words, the energy level must be changed. Such an experiment is called inelastic. On the other hand, any experiment in which the energy level of the nucleus stays undisturbed must last a very long time. Therefore such an “elastic” experiment can reveal only a time exposure.

IV. Give the situations from the text in which the following

Words are used:

To resemble; to deliver; to scatter; to yield; to expose; to excite; subsequent; shift; root; to involve.

V. Give questions to which the following statements

Might be the answer:

1. The first method most closely resembles ordinary vision.

2. In most such experiments one records only those electrons that have been simply scattered by the nucleus without exciting it.

3. The second method, like the first, involves the interaction of an electron with the nucleus.

4. Since the nucleus itself remains unexcited, this method yields a time exposure of the nucleus.

5. Some recent experiments of this type depend on X-ray spectra rather than optical spectra.

6. In the past few years such X-ray experiments have also been done with mu-mesonic atoms.

7. When an atom is excited by an input of energy, its electrons change their orbits.

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Lesson 58-61