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 GRE 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:
Your score will improve and your results will be more realistic
Is there something wrong with our timer?Let us know!
Upwards of a billion stars in our galaxy have burnt up their
[#permalink]
13 Aug 2020, 10:49
1
Expert Reply
2
Bookmarks
A
B
C
D
E
A
B
C
D
E
A
B
C
D
E
Upwards of a billion stars in our galaxy have burnt up their internal energy sources, and so can no longer produce the heat a star needs to oppose the inward force of gravity. These stars, of more than a few solar masses, evolve, in general, much more rapidly than does a star like the Sun. Moreover, it is just these more massive stars whose collapse does not halt at intermediate stages (that is, as white dwarfs or neutron stars). Instead, the collapse continues until a singularity (an infinitely dense concentration of matter) is reached .
It would be wonderful to observe a singularity and obtain direct evidence of the undoubtedly bizarre phenomena that occur near one. Unfortunately in most cases a distant observer cannot see the singularity; outgoing light rays are dragged back by gravity so forcefully that even if they could start out within a few kilometers of the singularity, they would end up in the singularity itself.
Question 1
00:00
A
B
C
D
E
Question Stats:
66% (02:15) correct
34% (02:21) wrong based on 41 sessions
HideShow
timer Statistics
25. The author's primary purpose in the passage is to
(A) describe the formation and nature of singularities (B) explain why large numbers of stars become singularities (C) compare the characteristics of singularities with those of stars (D) explain what happens during the stages of a singularity's formation (E) imply that singularities could be more easily studied if observers could get closer to them
44% (01:10) correct
56% (01:29) wrong based on 36 sessions
HideShow
timer Statistics
26. The passage suggests which of the following about the Sun?
I. The Sun could evolve to a stage of collapse that is less dense than a singularity. II. In the Sun, the inward force of gravity is balanced by the generation of heat. III. The Sun emits more observable light than does a white dwarf or a neutron star.
(A) I only (B) III only (C) I and II only (D) II and III only (E) I, II, and III
69% (01:21) correct
31% (01:23) wrong based on 32 sessions
HideShow
timer Statistics
27. Which of the following sentences would most probably follow the last sentence of the passage?
(A) Thus, a physicist interested in studying phenomena near singularities would necessarily hope to find a singularity with a measurable gravitational field. (B) Accordingly, physicists to date have been unable to observe directly any singUlarity. (C) It is specifically this startling phenomenon that has allowed us to codify the scant information currently available about singularities. (D) Moreover, the existence of this extraordinary phenomenon is implied in the extensive reports of several physicists. (E) Although unanticipated, phenomena such as these are consistent with the structure of a singularity.
Upwards of a billion stars in our galaxy have burnt up their
[#permalink]
17 Aug 2020, 05:31
2
Q25
A- Correct. The primary purpose here is to just tell us the nature and formation of the singularities. B- Is a part of the passage but not the primary purpose. C- Same as B D- There is no mention of specific stages of the singularity E- The opposite is actually implied given the last few lines
Q26
I- We are told that "these stars, of more than a few solar masses, evolve, in general, much more rapidly than does a star like the Sun." Since the other stars evolve into singularities it can be inferred that sun's evolution will have a mass less than the singularity. Correct. II- The other stars have burnt up their internal energy sources, and so can no longer produce the heat a star needs to oppose the inward force of gravity. This is not true of the sun as suggested by this option and is therefore correct. III- There is no mention of a comparison of observable light. Incorrect.
Q27
A- The gravitation force is so large that a measuring field is an illogical suggestion. B- The last sentence tells us why its difficult to observe a singularity. B just adds onto this by saying that physicists to date have been unable to observe directly any singularity. Correct. C- Quite the opposite. It's because of the phenomenon that we can't understand much. D- Irrelevant and thus incorrect. E- Same as D.
Re: Upwards of a billion stars in our galaxy have burnt up their
[#permalink]
12 Jun 2024, 03:48
Hello from the GRE Prep Club VerbalBot!
Thanks to another GRE Prep 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.
gmatclubot
Re: Upwards of a billion stars in our galaxy have burnt up their [#permalink]