Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.
Customized for You
we will pick new questions that match your level based on your Timer History
Track Your Progress
every week, we’ll send you an estimated GMAT score based on your performance
Practice Pays
we will pick new questions that match your level based on your Timer History
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
Thank you for using the timer!
We noticed you are actually not timing your practice. Click the START button first next time you use the timer.
There are many benefits to timing your practice, including:
In this conversation with Ankit Mehra, IESE MBA and CEO & Co-Founder, of GyanDhan, we will discuss how prospective MBA students can finance their MBA education with education loans and scholarships.
What do András from Hungary, Pablo from Mexico, Conner from the United States, Giorgio from Italy, Leo from Germany, and Rishab from India have in common? They all earned top scores on the GMAT Focus Edition using the Target Test Prep course!
Grab 20% off any Target Test Prep GMAT Focus plan during our Flash Sale. Just enter the coupon code FLASH20 at checkout to save up to $320. The offer ends on Tuesday, April 30.
After just 3 months of studying with the TTP GMAT Focus course, Conner scored an incredible 755 (Q89/V90/DI83) on the GMAT Focus. In this live interview, he shares how he achieved his outstanding 755 (100%) GMAT Focus score on test day.
What do András from Hungary, Conner from the United States, Giorgio from Italy, Leo from Germany, and Saahil from India have in common? They all earned top scores on the GMAT Focus Edition using the Target Test Prep course!
Spurred by the discovery that a substance containing uranium
[#permalink]
07 Sep 2005, 05:37
1
Kudos
Spurred by the discovery that a substance containing uranium emitted radiation, Marie Curie began studying radioactivity in 1897. She first tested gold and copper for radiation but found none. She then tested pitchblende, a mineral that was known to contain uranium, and discovered that it was more radioactive than uranium. Acting on the hypothesis that pitchblende must contain at least one other radiactive element, Curie was able to isolate a pair of previously unknown elements, polonium and radium. Turning her attention to the rate of radioactive emission, she discovered that uranium emitted radiation at a consistent rate, even if heated or dissolved. Based on these results, Curie concluded that the emission rate for a given element was constant. Furthermore, because radiation appeared to be spontaneous, with no discernible difference between radiating and nonradiating elements, she was unable to postulate a mechanism by which to explain radiation.
It is now known that radiation occurs when certain isotopes (atoms of the same element that differ slightly in their atomic structure) decay, and that emission rates are not constant but decrease very slowly with time. Some critics have recently faulted Curie for not reaching these conclusions herself, but it would have been impossible for Curie to do so given the evidence available to her. While relatively light elements such as gold and copper occasionally have unstable (i.e., radioactive) isotopes, radioactive isotopes of most of these elements are not available in nature because they have largely finished decaying and so have become stable. Conversly, heavier elements such as uranium, which decay into lighter elements in a process that take billion years, are present in nature exclusively in radioactive form.
Furthermore, we must recall that in Curie's time the nature of the atom itself was still being debated. Physicists believed that matter could not be divided indefinitely but instead would eventually be reduced to its indivisble components. Chemists, on the other hand, observing that chemical reactions took place as if matter was composed of atomlike particles, used the atom as the foundation for conceptualizing and describing such reactions - but they were not ultimately concerned with the question of whether or not such indivisible atoms actually existed.
As a physicist, Curie conjectured that radiating substances might lose mass in the form of atoms, but this idea is very different from the explanation eventually arrived at. It was not until the 1930s that advances in quantam mechanics overthrew the earlier understanding of the atom and showed that radiation occurs because the atoms themselves lose mass- a hyphothesis that Curie, committed to the indivisble atom, could not be expected to have conceived of. Moreover, not only is Curie's inability to identify the mechanism by radiation occurs, understandable, it is also important to recognize that it was Curie's investigation of radiation that paved the way for the later breakthroughs.
9) The passage suggests that the author would be most likely to agree with which one of the following statements about the comtemporary critics of Curie's studies of radioactivity?
A) The critics fail to take into account the obstacles Curie faced in dealing with the scientific community of her time
B) The critics do not appreciate that the eventual development of quantam mechanims depended on Curie's conjecture that radiating substances can lost atoms
C) The critics are unaware of the differing conceptions of the atom held by physicists and chemists
D) The critics fail to appreciate the importance of the historical context in which Curie's scientific conclusions were reached
E) The critics do not comprehend the intricate reasoning that Curie used in discovering polonium and radium.
12. The primary function of the first paragraph of the passage is
A) narrate the progress of turn-of-the-century studies of radioactivity.
B) present a context for the conflict between physicists and chemists
C) provide the factual background for an evaluation of Curie's work
D) outline the structure of the author's central argument
E) identify the error in Curie's work that undermines its usefulness
13) Which one of the following most accurately expresses the meaning of the word "mechanism" as used by the author in the last sentence of the first paragraph?
A) the physical process that underlies a phenomenon
B) the experimental apparatus in which a phenomenon arises
C) the procedure scientists use to bring about the occurrence of a phenomenon
D) the isotopes of an element needed to produce a phenomenon
E) the scientific theory describing a phenomenon.
Archived Topic
Hi there,
This topic has been closed and archived due to inactivity or violation of community quality standards. No more replies are possible here.
Still interested in this question? Check out the "Best Topics" block below for a better discussion on this exact question, as well as several more related questions.
Re: Spurred by the discovery that a substance containing uranium
[#permalink]
07 Sep 2005, 12:45
Hi Gmataquaguy,
I am replying in response to your PM.
My answers are 9D, 12C and 13A
9) A, B and C are too narrow. E is not mentioned in the passage. The critics definitely did not comprehend the historical context, when Curie made her discovery
12) A is wrong, because the author is definitely not giving a historical narrative on radioactivity. B is not mentioned in the first para. D is wrong because the author doesn't even mention the critics in the first para, and the author's central argument basically refutes the critics's assertion. E is wrong, the first para does not identify any error, nor does it classify Curie's findings as an error. C is correct because the first para gives a background of Curie's work.
13) The answer is not B, C or D. I chose A over E. I am not very confident about my answer choice, but A seems the best.
Re: Spurred by the discovery that a substance containing uranium
[#permalink]
07 Sep 2005, 12:46
I'm going to say 9. D), 12. C), and 13. E)
9. Critics didn't take into account the evidence available to Currie. Also the nature of the atom was still being debated during her time period. Go with D.
12. The whole passge was an evaluation of her work, factual info presented in the first paragraph therfore C.
Re: Spurred by the discovery that a substance containing uranium
[#permalink]
09 Sep 2005, 07:28
Darth_McDaddy wrote:
12) A is wrong, because the author is definitely not giving a historical narrative on radioactivity. B is not mentioned in the first para. D is wrong because the author doesn't even mention the critics in the first para, and the author's central argument basically refutes the critics's assertion. E is wrong, the first para does not identify any error, nor does it classify Curie's findings as an error. C is correct because the first para gives a background of Curie's work.
I was torn between A and C. Even if i had an extra hour, i would still have mulled over A and C. Here is how i interpreted AC A, "narrate the progress of the turn-of-the-century studies of radioactivity"
the author talks about the "advancements" made by Marie Curie since 1897 - discovery #1: pitchblende was more radioactive than radium. She then takes radiation understanding a step further - discovery #2: She isolated and discovered previously unknown elements - polonium and radium. Discovery #3: Emission rate was constant for a given element (Albeit, this was proved wrong later). The word "studies" [as opposed to study] is also applicable because she did a whole bunch of stuff that yielded discovery1, discovery2, discovery3. Granted "studies" could be interpreted to mean multiple people doing a study.
I thought AC C was equally applicable too. Couldnt decide between A and C, and picked A. Any thoughts on what is wrong with the aforementioned logic?
Darth_McDaddy wrote:
13) The answer is not B, C or D. I chose A over E. I am not very confident about my answer choice, but A seems the best.
I was torn between AC A and C. I picked C because she talks about not knowing how to discern the difference between when certain elements radiate and when other elements dont. So i thought that AC C, with the "bring about the occurence of a phenomenon" phrase summarized my thoughts accurately. However, i couldnt eliminate AC A either and "guessed".
Let me know your thoughts on where my logic brokedown.
Re: Spurred by the discovery that a substance containing uranium
[#permalink]
09 Sep 2005, 12:50
Hello Gmataquaguy,
I like the way you analyze your answer choices, and more importantly the way you revisit answer choices that you got wrong. That's the best way you can ensure how not to make the same mistake again. Enuf said!! Back to your question.
In question 12, I can see where you went wrong. It looks like you are focussing on the first para as it were standing on its own - with no connection to the entire passage. That is the reason, you viewed the first para as a narration of a series of studies and discovery on radioactivity. If you read the entire passage, and consider the first para as integral to the passage, you will realize that the first para is not opinionate, and is stating facts about Madame Curie's studies on radioactivity. Therefore C is the best answer. (Quick Tip. You can also narrow down your choices to those that focus on Curie, because Curie's work is the central focus of the first para)
In Question 13, read the sentence where the word mechanism occurs "Moreover, not only is Curie's inability to identify the mechanism by radiation occurs, understandable, it is also important to recognize ...". Understand the role, the word "mechanism" plays in this sentence. You will realize that it is not a procedure that scientists use to bring about a phenomenon. If it were, the sentence would read "... Curie's inability to develop the mechanism by which radiation occurs". If you understand this distinction, it would become clear that radiation, is a phenomenon that occurs without any intervention (atleast in the context of this passage). Thus the answer is A. Looking back, I am not sure why I had shortlisted E. The way radiation works is certainly not a scientific theory. It is a fact.
Sorry, for my very wordy explanation.
Hope it helped.
Re: Spurred by the discovery that a substance containing uranium
[#permalink]
09 Sep 2005, 13:20
Good one....
I got D, C and A as answer choice.
What is the OA.
--== Message from the GMAT Club Team ==--
THERE IS LIKELY A BETTER DISCUSSION OF THIS EXACT QUESTION. This discussion does not meet community quality standards. It has been retired.
If you would like to discuss this question please re-post it in the respective forum. Thank you!
To review the GMAT Club's Forums Posting Guidelines, please follow these links: Quantitative | Verbal Please note - we may remove posts that do not follow our posting guidelines. Thank you.
Re: Spurred by the discovery that a substance containing uranium
[#permalink]
28 Jun 2020, 11:47
Hello from the GMAT Club VerbalBot!
Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).
Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
Archived Topic
Hi there,
This topic has been closed and archived due to inactivity or violation of community quality standards. No more replies are possible here.
Still interested in this question? Check out the "Best Topics" block above for a better discussion on this exact question, as well as several more related questions.
Thank you for understanding, and happy exploring!
gmatclubot
Re: Spurred by the discovery that a substance containing uranium [#permalink]