Classical physics defines the vacuum as a state of absence: a vacuum

4 mins 57 secs... all correct! Wohooo The kind of passage that I like...straightforward and well written with some information to learn at the end of it.



Really weird question if you do not understand the main point - vacuum is being discussed with two aspects in mind - normal vacuum (with its fluctuations) and special vacuum decay by being next to nucleus and possible theory being confirmed by experiment
Which of the following titles best describes the passage as a whole?
(A) The Vacuum: Its Fluctuations and Decay Crystal clear choice among the given options
(B) The Vacuum: Its Creation and Instability No, the creation of vacuum is out of scope.
(C) The Vacuum: A State of Absence TRAP? only the first line could lead to this one but does not summarize the passage well
(D) Particles That Materialize in the Vacuum too detailed to be the title
(E) Classical Physics and the Vacuum TRAP - even though this is the start - we are talking about other things throughout the passage

Cleverly worded detail question
According to the passage, the assumption that the introduction of a real particle into a vacuum raises the total energy of that region of space has been cast into doubt by which of the following?
(A) Findings from laboratory experiments Nope, the finding is based on theory and we are trying to conduct experiments to verify it.
(B) Findings from observational field experiments Discard for same as above
(C) Accidental observations made during other experiments Again, no observations.
(D) Discovery of several erroneous propositions is accepted theories Again, no discoveries from erroneous propositions - not mentioned.
(E) Predictions based on theoretical' work Perfect - verbatim from the passage

Options on this one are tricky because they have two parts - charged vacuum and particles - we need to be clear that a charged vacuum "decays" and creates "real" particles
It can be inferred from the passage that scientists are currently making efforts to observe which of the following events?
(A) The decay of a vacuum in the presence of virtual particles Nope - decay is in the presence of a charge and results in real particles
(B) The decay of a vacuum next to a superheavy atomic nucleus Right - even though this has less info than the other options this is correct
(C) The creation of a superheavy atomic nucleus next to an intense electric field 180 opposite choice - we are not creating the atomic nucleus ( even if we are that is not the point, it is only a means to an end)
(D) The creation of a virtual electron and a virtual positron as a result of fluctuations of a vacuum similar to option one
(E) The creation of a charged vacuum in which only real electrons can be created in the vacuum's region of space MAJOR TRAP - a lot of words that we are looking for but again not the crux of what is happening in the experiment - we are doing the experiment for "decay of vacuum"

We are looking for the following structure: Theoretical finding -> possible in real-world -> requires some experiment to possibly confirm it
Physicists' recent investigations of the decay of the vacuum, as described in the passage, most closely resemble which of the following hypothetical events in other disciplines?
(A) On the basis of data gathered in a carefully controlled laboratory experiment, a chemist predicts and then demonstrates the physical properties of a newly synthesized polymer. Again , data gathered first is reverse of what we are trying to do.
(B) On the basis of manipulations of macroeconomic theory, an economist predicts that, contrary to accepted economic theory, inflation and unemployment will both decline under conditions of rapid economic growth. The first few words are a giveaway and the rest of the option confirms. Still, we need to look at other options and rule them out
(C) On the basis of a rereading of the texts of Jane Austen's novels, a literary critic suggests that, contrary to accepted literary interpretations, Austen's plots were actually metaphors for political events in early nineteenth-century England. Rereading of texts is not a theoretical finding - discard.
(D) On the basis of data gathered in carefully planned observations of several species of birds, a biologist proposes a modification in the accepted theory of interspecies competition. Data gathered first - discard fast
(E) On the basis of a study of observations incidentally recorded in ethnographers' descriptions of non-Western societies, an anthropologist proposes a new theory of kinship relations. Discard fast for same reason as above.

finally a straightforward question from the passage
According to the passage, the author considers the reduction of energy in an empty region of space to which a real particle has been added to be

(A) a well-known process not at all. 180 opposite
(B) a frequent occurrence same as above
(C) a fleeting aberration fleeting word is TRAP - the real particles created are long lasting - abberation again is clumsy - it is surprising find.
(D) an unimportant event then why would we discuss it? Not mentioned so discard.
(E) an unexpected outcome Perfect - infact this is verbatim from the passage ( marked in purple above)

Easy-cheesy detail question
According to the passage, virtual particles differ from real particles in which of the following ways?

I. Virtual particles have extremely short lifetimes. CORRECT
II. Virtual particles are created in an intense electric field. OPPOSITE
III. Virtual particles cannot be detected directly. CORRECT

(A) I only
(B) II only
(C) Ill only
(D) I and II only
(E) I and III only Tick.

Start your critical reasoning engine - we want to look out for anything that goes against the theory mentioned
The author's assertions concerning the conditions that lead to the decay of the vacuum would be most weakened if which of the following occurred?
(A) Scientists created an electric field next to a vacuum, but found that the electric field was not intense enough to create a charged vacuum. Not against the theory - discard
(B) Scientists assembled a superheavy atomic nucleus next to a vacuum, but found that no virtual particles were created in the vacuum's region of space. TRAP - we are not looking for virtual particles at all - but for real ones. Discard.
(C) Scientists assembled a superheavy atomic nucleus next to a vacuum, but found that they could not then detect any real particles in the vacuum's region of space. PERFECT - a needle in a haystack - need to stay focussed and look out for what we know about the theory and then negate it.
(D) Scientists introduced a virtual electron and a virtual positron into a vacuum's region of space, but found that the vacuum did not then fluctuate. Opposite of what makes up the experiment. Discard.
(E) Scientists introduced a real electron and a real positron into a vacuum's region of space, but found that the total energy of the space increased by the energy equivalent of the mass of the particles. Discard for same reason as above!

Phew! That was one long post. Hope the explanations are helpful.
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Hi gladiator 59

Question 4 was a total bummer. Do share your thoughts.


Best,
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I guess bummer means a mess or a nightmare.

However, you have to understand the passage as a whole to reply to such type of question and one way is to notice shift words or transition in the passage

Classical physics defines the vacuum as a state of absence:

the vacuum becomes somewhat more complicated.

One might expect that the vacuum would always be the state of lowest possible energy for a given region of space.

A surprising result of some recent theoretical investigations is that this assumption is not invariably true.

Experiments attempting to achieve this are now underway.

(B) On the basis of manipulations of macroeconomic theory, an economist predicts that, contrary to accepted economic theory, inflation and unemployment will both decline under conditions of rapid economic growth.

This is the answer that more closely resembles the phrases above.

Hope is clear now. You must read and read very carefully and using a proactive process.

Regards
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ShankSouljaBoi, Looks like you wanted to tag me... need to keep the "59" attached to "gladiator" to be able to do that

Hope the above post answers your doubt if you had any left after the great explanation from carcass. Let me know.

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Explain the question and get a Kudos!