Classified as a Cepheid variable and about 500 to 800 light-years from

Question

Classified as a Cepheid variable and about 500 to 800 light-years from Earth, Polaris, the North Star, has long been known as a pulsating star that dims and then brightens approximately every four days. If new findings are correct, Polaris now appears to be changing into a star whose brightness remains constant, providing scientists the unique opportunity to witness sidereal evolution. The latest observations apparently point to the cessation of pulsations within a few years. The results of these studies also suggest that the four-day pulsation period is slowly lengthening, and establish that this decline is occurring gradually rather than by abrupt jumps, slowing as the star ages, cools, and expands. More surprisingly, the pulsations themselves--even as they slow down--now appear to be fading away. This drop in amplitude suggests a cessation of the internal conditions that drive the pulsations will result in a disappearance of the pulsations.

Current interpretation suggests that we may be observing the star as it moves out of its phase of pulsational instability. Cepheids spend 40,000 years or more in an unstable, pulsating phase before reaching non-pulsing stability, and accordingly, the chance of observing a star during its transition, which lasts only a short time, is small. Rare as this event may be, it provides the most logical explanation of the decline in both the frequency and the amplitude of the star’s pulsations.

Current interpretation suggests that we may be observing the star as it moves out of its phase of pulsational instability. Cepheids spend 40,000 years or more in an unstable, pulsating phase before reaching non-pulsing stability, and accordingly, the chance of observing a star during its transition, which lasts only a short time, is small. Rare as this event may be, it provides the most logical explanation of the decline in both the frequency and the amplitude of the star’s pulsations.   1 
 1. The primary purpose of the passage is to

A. refute the conventional explanation for the stellar behavior of Polaris
B. provide an interpretation of recently observed phenomena
C. present evidence that confirms an unorthodox theory
D. confirm the value of a recent research project
E. defend an established theory against unwarranted attacks

2 
 2. According to the passage, the pulsations of a Cepheid variable most probably cease

A. when the star is no more than 40,000 years old
B. soon after the interior forces creating pulsation cease
C. as the star enters its transformational phase
D. with the onset of cooling and expansion
E. when the star's pulsation period shortens to fewer than four days

3 
 3. The author mentions that Polaris is aging, cooling and expanding in order to

A. describe the definitive characteristics of stars classified as Cepheid variables
B. explain the importance attached to the study of Polaris
C. describe the effects that internal conditions have on the brightness of Polaris
D. provide an explanation for the incremental lengthening of the star's pulsations
E. raise doubts about the traditional description of Polaris as stable

4 
 4. It can be inferred from the passage that the author believes which of the following about Cepheid variables?

A. They are often a part of major constellations.
B. Their pulsations are difficult to detect.
C. They eventually reach a stable, non-pulsating state.
D. They are fewer than 800 light-years from the earth.
E. They undergo a lengthy transition between phases.

5 
 5. The author would most likely argue that which of the following descriptions is most analogous to the gradually slowing pulsations of Polaris?

A. Water in a beaker contract as it cools until it reaches a point just above freezing, after which it begins to expand, and continues to expand through its phase change into ice.
B. The echo off a canyon wall takes longer to return to a listener as the origin of the noise moves further away from the wall.
C. A tuning fork is struck, giving off a high-pitched tone, and the pitch gets lower as the vibration of the tines slows over time.
D. An unevenly weighted lump of clay begins to rotate in an eccentric manner as a potter's wheel increases its speed of revolution.
E. The earth's moon goes through a nightly cycle of becoming more visible until it is in its full phase, and then incrementally wanes until it is no longer visible.

6 
 6. The passage suggests that all of the following are accurate statements about Polaris EXCEPT

A. Its distance from the earth has not been precisely established.
B. Its pulsations are now longer than the four-day period previously recorded.
C. It can be located in the Northern hemisphere of the night sky.
D. The amplitude of its pulsations has been declining for 40,000 years.
E. Its current transition status is a comparatively brief phase.

7 
 7. The passage suggests that the pulsations of Polaris can be expected to

A. continue to decline in both frequency and amplitude as the star becomes more stable
B. continue at the current rate of frequency and degree of amplitude indefinitely
C. build in frequency and drop in amplitude until the star reaches a stable state
D. increase in both frequency and amplitude as the star leaves its unstable phase
E. remain perceptible and stable for at least 40 QO0 years while internal forces cease

Sajjad1994 · Answer

Question 3:

From the OE.

Choice C:  While this choice may seem appealing because the passage states that  this drop in amplitude suggests a cessation of the internal conditions that drive the pulsations will result in a disappearance of the pulsations , this choice is a  memory trap.  Internal conditions are having an effect on the pulsations, not the brightness of Polaris. That is why  C  is incorrect.

shauryahanda · Answer

explanation 
Q1 - not going by options cause i feel the right way to approach such ques is nt by options but by thinking abt the purpose by yourself first

Purpose - To discuss and explain why The star has started reducing the frequency of flickering

Options that come close - B and D
D - wrong as the structure of psg has not been made in a way that an argument is being defended or an argument has been mentioned and then we are defending it 
So ans - B

2 - straight from psg "This drop in amplitude suggests a cessation of the internal conditions that drive the pulsations will result in a disappearance of the pulsations."

3 - same as mentioned by  Sajjad1994 
- drop in amplitude is nt the pt , drop in frequency is the pt

Sajjad1994 · Answer

Question 5:

One has to read the complete passage to answer this question, in the passage there is no concrete evidence or reason provided for the pulsations of Polaris or gradually slowing pulsations of Polaris. Different scenarios are provided in which the pulsation of Polaris is slowing down but not the main reason.

A. Water in a beaker contracts as it cools  until it reaches a point just above freezing , after which it begins to expand, and continues to expand through its phase change into ice.

B. The echo off a canyon wall takes longer to return to a listener as the origin of the noise  moves further away from the wall.

C. A tuning fork is struck, giving off a high-pitched tone, and the pitch gets lower as the vibration of the tines slows over time.

D. An  unevenly weighted  lump of clay begins to rotate in an eccentric manner as a  potter's wheel increases its speed of revolution.

E. The earth's moon goes through a  nightly cycle of becoming more visible  until it is in its full phase, and then incrementally wanes until it is no longer visible.

Due to the text in Red in above incorrect options the answer choices are not a fit analogy. Only C is better one.

Answer: C

MalharPagay · Answer

Can someone explain why Option C in question 4 is the right answer to an inference question, even though the passage explicitly states what is given in Option C. Additionally, wouldn't Option E be more accurate for the same question?
 Bunuel   CrackVerbal

Sajjad1994 · Answer

Hi MalharPagay

If you read the passage again you might come to know that  E  is a bit awkward and extreme to consider for the answer, the words  "lengthy transition"  make this option out of the scope of the passage. On the other hand,  C  is very straight forward and lies within the boundaries of the passage.

PS: Mostly test makers trap the test takers by using the information in the answer choice which is explicitly written in the passage but it is not the case at all the times. So if the answer option is containing information which can be explicitly validated by the passage the answer choice might not the trap in this case we make sure the answer by reading and comparing the remaining choices.

Thank you

Sajjad1994 · Answer

Explanation

7. The passage suggests that the pulsations of Polaris can be expected to

Explanation

First, read the question then find the support of the answer in the passage, below is the text from the passage which to the answer:

The results of these studies also suggest that the four-day pulsation period is slowly lengthening, and establish that this decline is occurring gradually rather than by abrupt jumps, slowing as the star ages, cools, and expands.

Another here

This drop in amplitude suggests a cessation of the internal conditions that drive the pulsations will result in a disappearance of the pulsations.

The perfect lead here

it provides the most logical explanation of the decline in both the frequency and the amplitude of the star’s pulsations.

Now read the answer choices

A. continue to decline in both frequency and amplitude as the star becomes more stable

Correct! according to the above text taken from the passage

B. continue at the current rate of frequency and degree of amplitude indefinitely

Out of scope of the passage

C.  build in frequency  and  drop in amplitude  until the star reaches a stable state

Trap: Half right and half wrong answer choice

D. increase in both frequency and amplitude as the star leaves its unstable phase

This is at 180, totally opposite.

E. remain perceptible and stable for at least 40 QO0 years while internal forces cease

Same as the  (B)  Out of scope of the passage

Answer: A

Sajjad1994 · Answer

Official Explanation

2. According to the passage, the pulsations of a Cepheid variable most probably cease

Explanation

This is a retrieval question, as shown by the words according to the passage. The task of the question is indicated by the words according to the passage. The subject of the question is when the pulsations of a Cepheid variable most probably cease. In order to answer this question, determine what the passage says about the subject, then evaluate each answer choice, eliminating any choice that cannot be supported by the text. The passage says cessation of the internal conditions that drive the pulsations will result in a disappearance of the pulsations.

Choice A: No.  This choice may be attractive because of the recycled phrase 40,000 years, but this choice is recycled language. The passage says Cepheids spend 40,000 years or more, which is quite different from no more than 40,000 years old.

Choice B:  Correct.   The passage says a cessation of the internal conditions that drive the pulsations will result in a disappearance of the pulsations.

Choice C: No.  While this choice may seem appealing because the passage states that there is a transition, which lasts only a short time, this choice is a memory trap. The transition may last only a short time, but the pulsations disappear at the end of the transition, not its beginning.

Choice D: No.  This choice is appealing, as the passage mentions pulsations slowing as the star ages, cools, and expands. However, this choice is a memory trap. The pulsations slow as the star cools and expands, but do not immediately cease.

Choice E: No.  While this choice may seem attractive because the passage says that the four-day pulsation period is slowly lengthening. But this is a reversal since the pulsation period is not shortening but lengthening.

The correct answer is choice B.

Sajjad1994 · Answer

Explanation

6. The passage suggests that all of the following are accurate statements about Polaris EXCEPT

Explanation

The question asks us to find what cannot be inferred from the passage. Let's read each option.

A. Its distance from the earth has not been precisely established.

Can be inferred: "Classified as a Cepheid variable and about 500 to 800 light-years from Earth,"

B. Its pulsations are now longer than the four-day period previously recorded.

Can be inferred from the first paragraph.

C. It can be located in the Northern hemisphere of the night sky.

This one is tough to find or infer from the passage but the only text which suggests this is: "Polaris, the  North Star ," This is a weak inference though. An official question or a quality question must have a strong logical inference.

D. The amplitude of its pulsations has been declining for 40,000 years.

This cannot be inferred, the only seemingly related text in the passage is "Cepheids spend 40,000 years or more in an unstable, pulsating phase before reaching non-pulsing stability"

But it does not suggest that the amplitude of its pulsations has been declining for 40,000 years. This seems ok.

E. Its current transition status is a comparatively brief phase.

Yes, it is brief and given in the first paragraph.

Answer: D

Classified as a Cepheid variable and about 500 to 800 light-years from

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Classified as a Cepheid variable and about 500 to 800 light-years from

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