Quantum Theory, although of tremendous scientific value

Question

Quantum Theory, although of tremendous scientific value, has nevertheless prompted debate among physicists. The debate arose because quantum theory addresses the peculiar properties of minute objects such as photons and electrons. While one type of experiment shows that these objects behave like particles, with well-defined trajectories through space, another demonstrates that, on the contrary, they behave like waves, their peaks and troughs producing characteristic “interference” effects. However, scientists have failed to devise an experiment to demonstrate both behaviors simultaneously.

In the 1920s, two alternate interpretations of quantum theory attempted to resolve this apparently contradictory wave-particle duality. Physicists Niel Bohr argued that wave particle properties are not contradictory, but complementary. Contrary to our intuition that an object continues to exist in some determined form even though we cannot perceive it, he concluded that the physical reality of a quantum objects is actually undetermined before the object is observed via experiment.

Physicists Werner Heisenberg's “uncertainty principle”, by contrast, postulated that we cannot precisely determine two complementary properties, such as position and momentum, of a quantum object simultaneously: if we measure an object's position with absolute certainty, then there is an infinite uncertainty in its momentum, and vice versa. He concluded that although we are limited in our ability to measure objects at the atomic and subatomic levels, their position and momentum are nonetheless defined all along.   1 
 1. Which of the following does the passage mention as providing evidence of the dual nature of quantum objects?

A. Scientists' inability to measure the position and momentum of quantum objects simultaneously.
B. Scientists' inability to measure the momentum of the quantum objects with certainty.
C. The similarities in the appearance of particles and waves.
D. The tendency of quantum objects to exhibit well-defined trajectories only at either extremely high or extremely low speeds.
E. The behavior of quantum objects as either particles or waves depending on the type of experiment that is performed.

2 
 2. It can be inferred from the passage that if scientists were able to measure the position and momentum of quantum objects precisely and simultaneously, then the

A. theory that the dual properties of quantum objects are complementary would be proven.
B. basic postulate of the uncertainty principle would be refuted 
C. distinction between particle behavior would cease to exist 
D. debate about quantum theory among physicists would be unchanged.
E. trajectories of quantum objects through space would be more difficult to predict.

3 
 3. All of the following are mentioned in the passage as possible characteristics of quantum objects except:

A. a minute size
B. momentum
C. position in space
D. sporadic movement 
E. wave like behavior

4 
 4. Which of the following, if true, would most seriously undermine Bohr's conclusion about the physical reality of a quantum object?

A. The physical properties of particles and waves are inherently complementary.
B. Human intuition is not a factor in the interpretation of scientific data about quantum objects.
C. Results of experiments on quantum objects are sometime influenced by the expectations of the experiments.
D. The technology used in research on quantum objects has made tremendous advances since the 1920s.
E. Quantum objects posses distinct, continuously existing physical forms that do not depend on the experiments used to measure them

5 
 5. The passage suggests that the debate among physicists mentioned in the first sentence has arisen in part because

A. the rapid movement of quantum objects poses an insurmountable obstacle to precise measurement
B. scientists have been unable to devise a single experiment that reveals both particle and wave properties of quantum objects simultaneously
C. the controversial nature of quantum theory has made it difficult for scientists to agree on what evidence is acceptable
D. division among physicists has resulted in the design of experiments that produce unintelligible experimental results
E. research efforts have been undermined by irreconcilable contradictions between equally compelling interpretations of quantum theory

6 
 6. Which of the following best describes the organization of the passage?

A. A thesis is introduced and then amended.
B. Arguments are presented, weighed, and then reconciled.
C. A problem is described and different interpretations intended to resolve the problem are presented.
D. Hypotheses are analyzed, their premises are refuted, and alternatives are suggested to replace the hypotheses.
E. A theory is advanced, opposing evidence is considered, and the theory is abandoned.

ID 00139

GMATNinja · Accepted Answer

Bohr's conclusion was "that the physical reality of a quantum object is actually determined before the object is observed via experiment." Even though this CONCLUSION is  contrary  to human intuition, Bohr's does NOT suggest that human intuition is not a  factor  in INTERPRETING scientific data. Human intuition might be used to  interpret  the data, and that analysis might yield CONCLUSIONS that are contrary to our intuition. Thus, choice (B) is not appropriate.

Bohr's conclusion is CONTRARY to the intuitive idea "that an object continues to exist in some determined form even though we cannot perceive it." Choice (E) says that the objects possess "distinct, continuously existing physical forms." Thus, choice (E) supports the intuitive idea. Since Bohr's conclusion OPPOSES the intuitive idea, choice (E) undermines Bohr's conclusion.

KarishmaB · Answer

You are ignoring the first part of this sentence:

Physicists Niel Bohr argued that wave particle properties are not contradictory, but complementary.  Contrary to our intuition that an object continues to exist in some determined form even though we cannot perceive it , he concluded that the physical reality of a quantum objects is actually determined before the object is observed via experiment.

What he concludes is contrary to "an object exists in some determined form". He says the physical reality is determined  before  being observed. It may not stay the same once we observe it.

e) Quantum objects posses distinct, continuously existing physical forms that do not depend on the experiments used to measure them
This is telling us that the object exists in some determined form. Bohr concluded against this. So this is against what Bohr says.

baanhgraduate · Answer

I chose B for Question 4 because the second paragraph mentions that "Contrary to our intuition that an object continues to ..." so that if human intuition is not a factor in the interpretation, Bohr's interpretation makes no sense.

What's wrong in my explanation?

About the answer E, I don't understand because the 2nd paragraph just says "... is observed via experiment", which does not mean the experiment affects the physical forms of the objects.

mbaapplicant2019 · Answer

5. The passage suggests that the debate among physicists mentioned in the first sentence has arisen in part because:

A: the rapid movement of quantum objects poses an insurmountable obstacle to precise measurement
B: scientists have been unable to devise a single experiment that reveals both particle and wave properties of quantum objects simultaneously
C: the controversial nature of quantum theory has made it for scientists to agree on what evidence is acceptable
D: division among physicists has resulted in the design of experiments that produce unintelligible experimental results
E: research efforts have been undermined by irreconcilable contradictions between equally compelling interpretations of quantum theory

Why C is not an answer ,please explain

ashisplb · Answer

Hi . Can anyone please justify the first question . I selected A as answer .

GMATNinja · Answer

The passage does mention scientists' inability to measure the position and momentum of quantum objects simultaneously (choice A), but this does not represent  evidence of the  dual nature  of quantum objects . Such evidence is presented in the first paragraph: "one type of experiment shows that   objects behave like particles" and "another   demonstrates that, on the contrary,   behave like waves". This corresponds to choice (E). This evidence demonstrates that quantum objects can behave like 1) waves and 2) particles and thus demonstrates the  dual nature  of quantum objects.

I hope that helps!

mSKR · Answer

Physicists Werner Heisenberg's “uncertainty principle”, by contrast,

What is contrast refer to here?
 Does it refer to 
-uncertainty principle?
- Physicists Niel Bohr argued that wave particle properties ?
- human intuition 
- interpretations of quantum theory

Please suggest GMATNinjaTwo ,  SajjadAhmad ,  GMATNinja

GMATNinja · Answer

The contrast is between the "two alternate interpretations of quantum theory" mentioned at the start of the second paragraph. These interpretations are Niel Bohr's argument that "wave particle properties are not contradictory, but complementary" and Werner Heisenberg's “uncertainty principle”. If that last sentence makes you think of Walter White, you have excellent taste in TV programs.

I hope that helps!

GMATNinja · Answer

The passage tells us the disagreement has arisen because one set of experiments demonstrate that "photons and electrons... behave like particles" and another set of experiments demonstrates that "they behave like waves" but "scientists have failed to devise an experiment to demonstrate both behaviors simultaneously."

However, the passage does not tell us that there is any disagreement about what  evidence is acceptable . Without this disagreement, answer choice (C) cannot be the correct answer to this question.

I hope that helps!

Harsh2111s · Answer

VeritasKarishma   GMATNinja 
I have doubt regarding option E.
Look at these lines from the passage
" he concluded that the  physical reality of a quantum objects is actually determined before  the object is observed via experiment."
When physical reality is already determined before experiment then even though quantum objects posses distinct forms that doesn't depend on experiments, it will have no effect on physical reality.
Option E supports Bohr's conclusion.
Please explain what I missed.

Emmakim · Answer

Where can I find any hint from the passage of Q3?
I can't understand what "Possible Characteristic" means..

Please kindly help.

GMATNinja · Answer

Question 3 
 
In the passage, the author reveals some strange things about quantum objects. There is debate over whether they act as particles or waves, and why they sometimes appear to be one of those things and not the other.

So, not all of the characteristics of quantum objects are  fully  understood -- some of them are just "possible" characteristics that may not hold true all of the time.

Question 3 asks us which answer choice is  not  mentioned as a possible characteristic. Here are the options:
 
This is mentioned as a characteristic of quantum particles in the first paragraph, when the author says that "quantum theory addresses the peculiar properties of  minute  objects."

Because (A) is mentioned, we can eliminate it.

(B) is mentioned in the third paragraph: "...two complementary properties, such as position and  momentum , of a quantum object..."

Eliminate (B).

The same sentence mentions (C): "...two complementary properties, such as  position  and momentum, of a quantum object..."

(C) is out.

The passage definitely mentions the movement of quantum objects, but doesn't say that this movement is  sporadic .

(D) is not mentioned, so hang onto it.

In the first paragraph, we learn that quantum particles sometimes "behave like waves." While this isn't a set-in-stone characteristic that always holds true, it is a possible characteristic of quantum objects.

(E) is mentioned as a possible characteristic of quantum objects, so eliminate (E).

(D) is the correct answer to question 3.

I hope that helps!

KittyDoodles · Answer

Hi Experts,

Please can you explain QS 2. I was stuck between A and B.

Thanks
Kitty

Sajjad1994 · Answer

Option a) "theory that the dual properties of quantum objects are complementary would be proven"  is incorrect because the passage does not provide evidence or suggest that the theory of complementary properties of quantum objects would be proven if scientists were able to measure the position and momentum of quantum objects precisely and simultaneously.

The passage mentions Niels Bohr's interpretation of quantum theory, which argues that the wave-particle duality of quantum objects is not contradictory but rather complementary, and that the physical reality of a quantum object is determined before it is observed. However, the passage does not state that this theory would be proven or disproven based on the ability to measure the position and momentum of quantum objects simultaneously.

The passage primarily focuses on the debate between Bohr's interpretation and Heisenberg's uncertainty principle, which postulates that there are inherent limits to the precision with which certain properties of quantum objects can be known. The ability to measure the position and momentum of quantum objects precisely and simultaneously would have implications for Heisenberg's uncertainty principle, as it would challenge the notion of inherent limits to measurement precision.

Therefore, option a) is not supported by the information provided in the passage, and the correct answer remains as b) basic postulate of the uncertainty principle would be refuted.

The correct answer is b) basic postulate of the uncertainty principle would be refuted.

The passage mentions Werner Heisenberg's uncertainty principle, which states that there is a fundamental limit to our ability to simultaneously measure certain complementary properties, such as position and momentum, of a quantum object. Heisenberg argued that this uncertainty is inherent to the nature of quantum objects and not due to any limitations in measurement technology.

If scientists were able to measure the position and momentum of quantum objects precisely and simultaneously, it would contradict Heisenberg's uncertainty principle, which forms the basis of his interpretation of quantum theory. This would mean that the basic postulate of the uncertainty principle, which states that there are inherent limits to the precision with which certain properties of quantum objects can be known, would be refuted.

Therefore, the correct answer is b) basic postulate of the uncertainty principle would be refuted. This would have significant implications for our understanding of quantum theory and may require a reevaluation of the interpretations proposed by Heisenberg and other physicists.

Engineer1 · Answer

KarishmaB

The correct word in the second paragraph is "undetermined" in the actual GMAT Prep Passage. "... quantum objects is actually  undetermined  before the object is observed via experiment.". This is unfortunately incorrect in the passage pasted above. I could not get to the entire passage on GMAT prep yet because it is throwing me random passages. So, I came here to complete the passage altogether. Anyhow, it seems like C is wrong. Could you help me explain why? Thanks!

KarishmaB · Answer

4. Which of the following, if true, would most seriously undermine Bohr's conclusion about the physical reality of a quantum object?

Well, that just makes it better and cleaner then. The answer is still in the same part of the same sentence,

Contrary to our intuition that an object continues to exist in some determined form even though we cannot perceive it , he concluded that the physical reality of a quantum objects is actually undetermined before the object is observed via experiment.

Our intuition says that an object continues to exist in some determined form even though we cannot perceive it. Bohr concluded against this intuition. This means that he says that an object does not exist in some determined form. There is no confusion here about 'before the experiment', 'during the experiment' or 'after the experiment.' With the changed wording, we are now given that he says that physical reality is undetermined before the object is observed so basically its all undetermined and we don't have to worry about the experiment.

e) Quantum objects posses distinct, continuously existing physical forms that do not depend on the experiments used to measure them.

This is opposite of what Bohr said and hence it undermines Bohr's conclusion.

c) Results of experiments on quantum objects are sometime influenced by the expectations of the experiments.

"Expectations of the experiments" is not a concept discussed in the passage. Hence, I do not know how to evaluate this. So it can't be the answer. After all, I am not required to know Quantum theory to be able to answer the RC questions. I only have to pick info from the passage.

Hence (E) makes sense.

Quantum Theory, although of tremendous scientific value

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Quantum Theory, although of tremendous scientific value

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