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Updated on: 02 Apr 2020, 03:37
Originally posted by AVRonaldo on 28 May 2015, 09:03.
Last edited by Sajjad1994 on 02 Apr 2020, 03:37, edited 4 times in total.
Last edited by Sajjad1994 on 02 Apr 2020, 03:37, edited 4 times in total.
Updated - Complete topic (260).
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Question 1
D
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
95%
(hard)
Question Stats:
31% (02:42) correct
69%
(03:06) wrong
based on 928
sessions
History
Date
Time
Result
Not Attempted Yet
Question 2
C
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
65%
(hard)
Question Stats:
42% (01:10) correct 58%
(01:23) wrong
based on 914
sessions
History
Date
Time
Result
Not Attempted Yet
Question 3
D
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
45%
(medium)
Question Stats:
58% (01:16) correct 42%
(01:34) wrong
based on 873
sessions
History
Date
Time
Result
Not Attempted Yet
Question 4
B
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
35%
(medium)
Question Stats:
59% (00:42) correct 41%
(00:44) wrong
based on 818
sessions
History
Date
Time
Result
Not Attempted Yet
Question 5
B
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
15%
(low)
Question Stats:
73% (01:05) correct 27%
(01:05) wrong
based on 556
sessions
History
Date
Time
Result
Not Attempted Yet
Question 6
D
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
45%
(medium)
Question Stats:
56% (01:13) correct 44%
(01:14) wrong
based on 536
sessions
History
Date
Time
Result
Not Attempted Yet
Question 7
E
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
25%
(medium)
Question Stats:
68% (01:06) correct 32%
(01:22) wrong
based on 502
sessions
History
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Time
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Not Attempted Yet
Since the inception of quantum mechanics, the many counter-intuitive aspects and results of the theory have provoked strong philosophical debates and many interpretations. Even fundamental issues, such as Max Born's basic rules concerning probability amplitudes and probability distributions, took decades to be appreciated by society and many leading scientists. Indeed, the renowned physicist Richard Feynman once said, "I think I can safely say that nobody understands quantum mechanics."
The Copenhagen interpretation—due largely to the Danish theoretical physicist Niels Bohr—remains the quantum mechanical formalism that is currently most widely accepted amongst physicists, some 75 years after its enunciation in the first quarter of the 20th century. According to this interpretation, the probabilistic nature of quantum mechanics is not a temporary feature that will eventually be replaced by a deterministic theory, but instead must be considered a final renunciation of the classical idea of "causality". It is also believed therein that any well-defined application of the quantum mechanical formalism must always make reference to the experimental arrangement, due to the complementarity nature of evidence obtained under different experimental situations.
Albert Einstein, himself one of the founders of quantum theory, disliked this loss of determinism in measurement. Einstein held that there should be a local hidden variable theory (also known as the local realism idea) underlying quantum mechanics and, consequently, that the present theory was incomplete. He produced a series of objections to the theory, the most famous of which has become known as the Einstein-Podolsky-Rosen paradox. John Bell showed that this "EPR" paradox led to experimentally testable differences between quantum mechanics and local realistic theories. Experiments have been performed confirming the accuracy of quantum mechanics, thereby demonstrating that the physical world cannot be described by any local realistic theory. The Bohr-Einstein debates and the experiments that followed provide a vibrant critique of the Copenhagen Interpretation from an epistemological point of view.
The Copenhagen interpretation—due largely to the Danish theoretical physicist Niels Bohr—remains the quantum mechanical formalism that is currently most widely accepted amongst physicists, some 75 years after its enunciation in the first quarter of the 20th century. According to this interpretation, the probabilistic nature of quantum mechanics is not a temporary feature that will eventually be replaced by a deterministic theory, but instead must be considered a final renunciation of the classical idea of "causality". It is also believed therein that any well-defined application of the quantum mechanical formalism must always make reference to the experimental arrangement, due to the complementarity nature of evidence obtained under different experimental situations.
Albert Einstein, himself one of the founders of quantum theory, disliked this loss of determinism in measurement. Einstein held that there should be a local hidden variable theory (also known as the local realism idea) underlying quantum mechanics and, consequently, that the present theory was incomplete. He produced a series of objections to the theory, the most famous of which has become known as the Einstein-Podolsky-Rosen paradox. John Bell showed that this "EPR" paradox led to experimentally testable differences between quantum mechanics and local realistic theories. Experiments have been performed confirming the accuracy of quantum mechanics, thereby demonstrating that the physical world cannot be described by any local realistic theory. The Bohr-Einstein debates and the experiments that followed provide a vibrant critique of the Copenhagen Interpretation from an epistemological point of view.
1. According to the passage, Einstein’s position regarding determinism in quantum mechanics was ___________________.
(A) unverifiable
(B) incomplete
(C) promising
(D) incorrect
(E) unfounded
2. According to the passage, all of the following are true about the Copenhagen interpretation except:
(A) It puts an important emphasis on the experimental arrangement
(B) It redefines the interpretation of cause and effect
(C) It was critiqued by both Einstein and Bohr
(D) It is well regarded in the scientific community
(E) It is difficult to understand
3. Which of the following can be inferred about the local hidden variable theory?
(A) It replaced most components of quantum theory
(B) It was mostly in line with John Bell’s discoveries
(C) It was proven by the Einstein-Podolsky-Rosen parado
(D) It predicted more determinism in measurement than quantum theory
(E) It agreed mainly with the predictions of Niels Bohr
4. The primary purpose of the passage above is to:
(A) Show that Einstein was wrong about quantum mechanics
(B) Discuss an important debate on one of the most challenging scientific theories of the 20th century
(C) Highlight the importance of quantum mechanics in the field of physics
(D) Illustrate how perplexing quantum mechanics is for scientists
(E) Argue that the Copenhagen interpretation is correct
5. Which of the following can be inferred about the Copenhagen interpretation of quantum mechanics?
(A) It views the probabilistic nature of quantum mechanics as temporary.
(B) It involves some loss of determinism in measurement.
(C) It was widely accepted when it was enunciated 75 years ago.
(D) It views the experimental arrangement as unimportant.
(E) It rejected many of Albert Einstein’s views and theories.
6. According to the passage, it can be inferred that Albert Einstein believed all of the following EXCEPT:
(A) the local hidden variable theory was an essential component in a complete theory of quantum mechanics.
(B) Niels Bohr was incorrect in some part of his interpretation of quantum mechanics.
(C) the Copenhagen interpretation of quantum mechanics was incomplete.
(D) experimentally testable differences exist between quantum mechanics and local realistic theories.
(E) some components of the quantum mechanics theory were correct.
7. The passage suggests which of the following:
(A) Niels Bohr and Max Born would most likely agree on rules concerning probability amplitudes
(B) Richard Feynman and Albert Einstein would most likely disagree about the difficulties relating to quantum mechanics
(C) Niels Bohr and Albert Einstein would most likely disagree about most aspects of quantum mechanics
(D) John Bell and Albert Einstein would most likely disagree about quantum mechanics
(E) Albert Einstein and Niels Bohr would most likely disagree about determinism in measurement
(A) unverifiable
(B) incomplete
(C) promising
(D) incorrect
(E) unfounded
2. According to the passage, all of the following are true about the Copenhagen interpretation except:
(A) It puts an important emphasis on the experimental arrangement
(B) It redefines the interpretation of cause and effect
(C) It was critiqued by both Einstein and Bohr
(D) It is well regarded in the scientific community
(E) It is difficult to understand
3. Which of the following can be inferred about the local hidden variable theory?
(A) It replaced most components of quantum theory
(B) It was mostly in line with John Bell’s discoveries
(C) It was proven by the Einstein-Podolsky-Rosen parado
(D) It predicted more determinism in measurement than quantum theory
(E) It agreed mainly with the predictions of Niels Bohr
4. The primary purpose of the passage above is to:
(A) Show that Einstein was wrong about quantum mechanics
(B) Discuss an important debate on one of the most challenging scientific theories of the 20th century
(C) Highlight the importance of quantum mechanics in the field of physics
(D) Illustrate how perplexing quantum mechanics is for scientists
(E) Argue that the Copenhagen interpretation is correct
Solution
Explanation: The Copenhagen interpretation was primarily discussed in the 2nd paragraph (and in the 3rd) so you should focus your attention there. (A) is contradicted in the second sentence of the second paragraph. It says that according to this interpretation the probabilistic nature is NOT temporary. (B), the correct answer, requires that you leverage the first sentence of the 3rd paragraph in combination with the second paragraph. In that sentence you learn that “Albert Einstein…disliked this loss of determinism in measurement” in reference back to the Copenhagen interpretation. From that you know that the Copenhagen interpretation involved some loss of determinism. For (C), you learn in the passage that it is widely accepted today, but you have no idea if that was the case 75 years ago. (D), like (A), is directly contradicted in the 2nd paragraph – it states that the arrangement IS important. For (E), you know that Albert Einstein did not like the loss of determinism in the Copenhagen interpretation, but you have no idea if the Copenhagen interpretation rejected MANY of his views and theories. Correct answer is (B).
Explanation: The Copenhagen interpretation was primarily discussed in the 2nd paragraph (and in the 3rd) so you should focus your attention there. (A) is contradicted in the second sentence of the second paragraph. It says that according to this interpretation the probabilistic nature is NOT temporary. (B), the correct answer, requires that you leverage the first sentence of the 3rd paragraph in combination with the second paragraph. In that sentence you learn that “Albert Einstein…disliked this loss of determinism in measurement” in reference back to the Copenhagen interpretation. From that you know that the Copenhagen interpretation involved some loss of determinism. For (C), you learn in the passage that it is widely accepted today, but you have no idea if that was the case 75 years ago. (D), like (A), is directly contradicted in the 2nd paragraph – it states that the arrangement IS important. For (E), you know that Albert Einstein did not like the loss of determinism in the Copenhagen interpretation, but you have no idea if the Copenhagen interpretation rejected MANY of his views and theories. Correct answer is (B).
(A) It views the probabilistic nature of quantum mechanics as temporary.
(B) It involves some loss of determinism in measurement.
(C) It was widely accepted when it was enunciated 75 years ago.
(D) It views the experimental arrangement as unimportant.
(E) It rejected many of Albert Einstein’s views and theories.
From your mental map of this passage, you should recognize that for this question, you need to look mostly in the last paragraph since that is the only place where Einstein is mentioned. As with any EXCEPT question, your job is to find evidence in the passage for or against each answer choice and carefully use process of elimination.
Choice (A) can be confirmed based on this sentence: “Einstein held that there should be a local hidden variable theory underlying quantum mechanics and, consequently, that the present theory was incomplete.” Since Einstein believed that without local hidden variable theory, quantum theory is incomplete, he must believe that it is essential to quantum theory. Because (A) is supported by the passage, it can be eliminated.
For (B), Einstein had issues with some part of the Copenhagen interpretation (he believes that it is incomplete), and therefore with the ideas of Bohr, one of its primary architects. The passage also references the “Bohr-Einstein debates” at the end of the last paragraph. From this you know Albert Einstein clashed about some part of theory and that Einstein believed that Bohr was incorrect about some portion of his interpretation. You can therefore eliminate choice (C).
(C) is fairly easy to prove as it is explicitly stated in the second sentence of the last paragraph and can be eliminated.
(D), the correct answer, is tricky. While it is discussed in the last paragraph, you do not know if Einstein believed it. It was John Bell who showed these experimentally testable differences and that those differences contradicted Einstein. However, the passage doesn’t mention whether Einstein accepted Bell’s work. Thus (D) is the one choice that you cannot conclude regarding Einstein’s beliefs.
For (E), since Einstein was one of the founders of quantum mechanics, you can be sure that he agreed with some of its components. The correct answer is (D).
Choice (A) can be confirmed based on this sentence: “Einstein held that there should be a local hidden variable theory underlying quantum mechanics and, consequently, that the present theory was incomplete.” Since Einstein believed that without local hidden variable theory, quantum theory is incomplete, he must believe that it is essential to quantum theory. Because (A) is supported by the passage, it can be eliminated.
For (B), Einstein had issues with some part of the Copenhagen interpretation (he believes that it is incomplete), and therefore with the ideas of Bohr, one of its primary architects. The passage also references the “Bohr-Einstein debates” at the end of the last paragraph. From this you know Albert Einstein clashed about some part of theory and that Einstein believed that Bohr was incorrect about some portion of his interpretation. You can therefore eliminate choice (C).
(C) is fairly easy to prove as it is explicitly stated in the second sentence of the last paragraph and can be eliminated.
(D), the correct answer, is tricky. While it is discussed in the last paragraph, you do not know if Einstein believed it. It was John Bell who showed these experimentally testable differences and that those differences contradicted Einstein. However, the passage doesn’t mention whether Einstein accepted Bell’s work. Thus (D) is the one choice that you cannot conclude regarding Einstein’s beliefs.
For (E), since Einstein was one of the founders of quantum mechanics, you can be sure that he agreed with some of its components. The correct answer is (D).
(A) the local hidden variable theory was an essential component in a complete theory of quantum mechanics.
(B) Niels Bohr was incorrect in some part of his interpretation of quantum mechanics.
(C) the Copenhagen interpretation of quantum mechanics was incomplete.
(D) experimentally testable differences exist between quantum mechanics and local realistic theories.
(E) some components of the quantum mechanics theory were correct.
Solution: E
Explanation: To answer this question, you must examine each agreement/disagreement in the answer choices and look for confirmation in the passage.
(E) is the only one that is guaranteed because determinism in measurement was the exact portion of the quantum theory that the two men disagreed upon.
For (A), no information is given about how Bohr feels about Born’s rules. Likewise in (B), no comparison is given between Feynman and Einstein.
(C) and (D) are both too strong as Bohr and Einstein almost surely do agree about many aspects (they were both involved in its development) but just disagree about determinism in measurement, and Bell and Einstein may or may not agree on quantum mechanics.
All you know is that Bell determined that it would be possible to see who is correct. Answer is (E).
Explanation: To answer this question, you must examine each agreement/disagreement in the answer choices and look for confirmation in the passage.
(E) is the only one that is guaranteed because determinism in measurement was the exact portion of the quantum theory that the two men disagreed upon.
For (A), no information is given about how Bohr feels about Born’s rules. Likewise in (B), no comparison is given between Feynman and Einstein.
(C) and (D) are both too strong as Bohr and Einstein almost surely do agree about many aspects (they were both involved in its development) but just disagree about determinism in measurement, and Bell and Einstein may or may not agree on quantum mechanics.
All you know is that Bell determined that it would be possible to see who is correct. Answer is (E).
(A) Niels Bohr and Max Born would most likely agree on rules concerning probability amplitudes
(B) Richard Feynman and Albert Einstein would most likely disagree about the difficulties relating to quantum mechanics
(C) Niels Bohr and Albert Einstein would most likely disagree about most aspects of quantum mechanics
(D) John Bell and Albert Einstein would most likely disagree about quantum mechanics
(E) Albert Einstein and Niels Bohr would most likely disagree about determinism in measurement
05 Jun 2015, 11:41
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can somebody give explanations for the answers..
Updated on: 17 Jun 2015, 03:18
Originally posted by HarishLearner on 17 Jun 2015, 02:52.
Last edited by HarishLearner on 17 Jun 2015, 03:18, edited 3 times in total.
Last edited by HarishLearner on 17 Jun 2015, 03:18, edited 3 times in total.
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ashish8814
can somebody give explanations for the answers..
Q1 - Answer D.
Reasons:
Einstein did not accept the probabilistic nature of quantum mechanics. According to the Copenhagen interpretation (para 2) (line 4) "the probabilistic nature of quantum mechanics is not a temporary feature that will eventually be replaced by a deterministic theory, but instead must be considered a final renunciation of the classical idea of "causality".
But Einstein felt that - (para 3) "Albert Einstein, himself one of the founders of quantum theory, disliked this loss of determinism in measurement. Einstein held that there should be a local hidden variable theory (also known as the local realism idea) underlying quantum mechanics and, consequently, that the present theory was incomplete."
Same Para -3, Line 8 - "Experiments have been performed confirming the accuracy of quantum mechanics, thereby demonstrating that the physical world cannot be described by any local realistic theory."
Clearly the experiments have proved that Einstein was wrong in postulating a local hidden variable theory(aka local realism idea). So yes, Choice D - incorrect- is the correct answer.
------------------------------------
Choice A - unverifiable - is wrong because EPR paradox was verified by John Bell and it led to " testable differences between quantum mechanics and local realistic theories. "
Choice B - incomplete - is wrong, because nowhere is it stated or implied that his objections were incomplete. Rather they were proven wrong.
Choice C - promising - is wrong because Einstein was proven wrong. (Penultimate Sentence of the Last Para - "Experiments have been performed confirming the accuracy of quantum mechanics, thereby demonstrating that the physical world cannot be described by any local realistic theory."
Choice E - unfounded - is wrong because Einstein was proven wrong - Also we cannot say his objections were unfounded - there was some basis for his objections.
