Rainbows have long been a part of religion and mythology in cultures a

Question

New Project RC Butler 2019  -  Practice 2 RC Passages Everyday   
Passage # 419, Date: 29-Oct-2019
 This post is a part of New Project RC Butler 2019 .  Click here for Details

Rainbows have long been a part of religion and mythology in cultures around the globe, appearing as bridges between the heavens and the earth, as messages from the gods, or as weapons wielded by divine powers. Some cultures have viewed rainbows themselves as deities, or even as demonic beings from which to hide children. But in the early fourteenth century, Theodoric of Freiburg, a German friar, and Kamal al-Din al-Farisi, a Persian scientist, independently turned a scientific eye to the study of rainbows.

Theodoric and al-Farisi were thousands of miles apart, but both had studied Ibn alHaytham’s Book of Optics. Each concluded that a rainbow’s appearance is the result of sunlight refracting and reflecting through water droplets left after a rainfall. They conducted experiments to provide support for their conclusions, successfully re-creating the conditions necessary to make a rainbow appear; al-Farisi used a sphere and a camera obscura, while Theodoric used flasks and globes.

Both scholars were, as modern physics has shown, correct in their assessments. When light hits a water droplet, the water causes the light’s speed to decrease. Furthermore, the light refracts—or changes direction—upon entering the droplet, and some of the light reflects off the back of the droplet, refracting again as it exits. The angle of refraction depends on the wavelength of the light; thus, refraction “breaks” white light into multiple wavelengths—a phenomenon called dispersion—which appear as different colors.

But for a rainbow to fill the sky with color, more is needed. A single droplet of water will disperse the entire visible light spectrum, with each wavelength leaving at a different angle, but it alone cannot create a rainbow.  Only a little of the light from a particular droplet reaches the eye of the human observer, striking the eye from a particular angle. For the observer to perceive the rainbow’s characteristic banded arc of different colors, a multitude of droplets suspended in the air, refracting and dispersing light, are needed, with the shorter wavelengths and shallower angles of indigo and violet appearing to the observer at the bottom and the longer wavelengths and steeper angles of red and orange appearing at the top.   1 
 D 
 1. The author mentions the angle at which light leaves water droplets ( Text in Red ) primarily in order to

(A) describe how refraction causes light to disperse as it leaves a water droplet
(B) show that indigo and violet appear at the bottom of rainbows because those colors have shallower angles
(C) illustrate that a change in the angle of light changes the wavelength of the light
(D) explain that the human eye perceives a rainbow only when light is refracted from multiple points
(E) introduce evidence that may help solve a long-standing mystery about the physics of refraction

2 
 E 
 2. Based on the passage, it can be inferred that the rainbow’s middle colors of yellow, green, and blue

(A) are not broken into separate bands by the dispersion of light leaving a droplet of water
(B) have longer wavelengths than do the red and orange light at the top of the rainbow
(C) have wavelengths that all strike the eye of a human observer at the same angle
(D) have wavelengths that are refracted at shallower angles than the wavelengths of indigo and violet light
(E) have wavelengths that are shorter than those of red and orange light and longer than those of indigo and violet light

3 
 C 
 3. According to the passage, the refraction of light upon entering and leaving a water droplet

(A) changes the angle at which light leaves the water droplet, thereby altering the light’s wavelength
(B) causes the light to be reflected and thus intensify, becoming more visible to the human observer
(C) disperses white light, allowing it to be seen as its different component colors
(D) causes the light to slow and thus more readily disperse according to its different wavelengths
(E) alters the light’s wavelengths so they fall within the visible spectrum

4 
 B 
 4. The primary purpose of the passage is to

(A) explain why rainbows are a relatively rare phenomenon 
(B) describe religious and scientific explanations for the appearance of rainbows
(C) raise doubts about a historical explanation for the appearance of rainbows
(D) explore the reasons that the refraction of light causes it to appear as different colors
(E) examine the physics underlying the appearance of rainbows to the human observer

5 
 A 
 5. It can be inferred that the author of the passage would most likely agree with which of the following statements about the study of rainbows?

(A) Scientific experiments performed hundreds of years ago sometimes provided accurate results.
(B) Cultures that associate rainbows with divinity do not approve of scientific inquiry into the nature of rainbows.
(C) The experiments of Theodoric and al-Farisi established that refraction of light occurs in water droplets but did not examine larger volumes of water.
(D) In societies in which the results of scientific studies of rainbows are widely accepted, rainbows are no longer associated with spiritual meaning.
(E) Studies such as Theodoric’s and al-Farisi’s now have no value because modern science has shown them to be simplistic.

6 
 E 
 6. The primary function of the second paragraph is to

(A) discuss a challenge to the conception of rainbows as a religious symbol
(B) evaluate two historical methods for observing rainbows
(C) describe the difficulties early scholars overcame in their attempts to understand rainbows
(D) support the idea that medieval science is similar in value to modern science
(E) outline historical attempts to understand the scientific basis of rainbows

Tracy95 · Answer

I am not very convinced about the result of question 4 and 5. 
Question 4: I think religious explanation serves as background information in the opening paragraph and so the primary purpose of the passage is about scientific explanations only. 
Question 5: I think 5A is sort of an exaggerated answer, or a generalization that goes quite far.

I appreciate any comment on my thinking so that I could be enlightened about why OAs are justified.

Hea234ven · Answer

Need a good explanation for the answer of q. 5

Posted from my mobile device

Skywalker18 · Answer

All correct except Q4 in 8 mins 45 seconds, including almost 4 mins to read.
Para 1- Rainbows in culture- deities, bridges, demons etc; Theodoric and al-Din al-Farisi scientific approach 
Para 2- Theodoric and al-Din al-Farisi scientific approach - result of sunlight refracting and reflecting through water droplets left after a rainfall; experiments
Para 3- modern physics explanation
Para 4- scientific details

1. The author mentions the angle at which light leaves water droplets ( Text in Red ) primarily in order to 
(D) explain that the human eye perceives a rainbow only when light is refracted from multiple points

Only a little of the light from a particular droplet reaches the eye of the human observer, striking the eye from a particular angle.  For the observer to perceive the rainbow’s characteristic banded arc of different colors, a multitude of droplets suspended in the air , refracting and dispersing light, are needed

2. Based on the passage, it can be inferred that the rainbow’s middle colors of yellow, green, and blue 
(E) have wavelengths that are shorter than those of red and orange light and longer than those of indigo and violet light
with the shorter wavelengths and shallower angles of indigo and violet appearing to the observer at the bottom and the longer wavelengths and steeper angles of red and orange appearing at the top

3. According to the passage, the refraction of light upon entering and leaving a water droplet 
(C) disperses white light, allowing it to be seen as its different component colors
The angle of refraction depends on the wavelength of the light; thus, refraction “breaks” white light into multiple wavelengths—a phenomenon called dispersion—which appear as different colors.

4. The primary purpose of the passage is to 
(A) explain why rainbows are a relatively rare phenomenon - incorrect, the passage does not mention that rainbows are relatively rare
(B) describe religious and scientific explanations for the appearance of rainbows
(C) raise doubts about a historical explanation for the appearance of rainbows- incorrect, scientific explanation was not provided to raise doubts on historical explanation. Rather modern physics supports the conclusion of Theodoric and al-Din al-Farisi.
Also, it does not seem that scienitific explanation was added to undermine cultural explanation- history and mythology
(D) explore the reasons that the refraction of light causes it to appear as different colors- incorrect, this is too narrow
(E) examine the physics underlying the appearance of rainbows to the human observer

I was down to options B and E but chose option E. I understand that option E does not cover the first para. I thought that para 1 was just providing some background information of rainbows.

AjiteshArun  ,  GMATNinja  ,  MagooshExpert  ,  GMATGuruNY  ,  VeritasPrepBrian  ,  MartyTargetTestPrep  ,  DmitryFarber  ,  VeritasKarishma  ,  generis  , other experts - please enlighten

5. It can be inferred that the author of the passage would most likely agree with which of the following statements about the study of rainbows?

(A) Scientific experiments performed hundreds of years ago sometimes provided accurate results.
Theodoric and al-Farisi were thousands of miles apart, but both had studied Ibn al-Haytham's Book of Optics. Each concluded that a rainbow’s appearance is the result of sunlight refracting and reflecting through water droplets left after a rainfall.

Both scholars were, as modern physics has shown, correct in their assessments.

6. The primary function of the second paragraph is to  
(E) outline historical attempts to understand the scientific basis of rainbows- Correct

But in the early fourteenth century, Theodoric of Freiburg, a German friar, and Kamal al-Din al-Farisi, a Persian scientist, independently turned a scientific eye to the study of rainbows.
The second para details the work of the two scientists

Sajjad1994 · Answer

Official Explanation

4. The primary purpose of the passage is to

Difficulty Level:   Hard

Explanation

STEP 1: ANALYZE THE QUESTION STEM

This is a Global question, asking for the primary purpose of the passage as a whole.

STEP 2: RESEARCH THE RELEVANT TEXT

There’s no need to review the whole passage. Use the passage map to find the purpose: to describe explanations for rainbows (mythology/science).

STEP 3: MAKE A PREDICTION

The correct answer will reflect the purpose in your passage map.

STEP 4: EVALUATE THE ANSWER CHOICES

(B)  matches the prediction and is correct. Whether or not rainbows are rare is not mentioned in the passage, so  (A) is incorrect.

(C)  is a 180, as the author confirms that the two historical explanations discussed are borne out by modern physics.

(D)  can be eliminated because this is merely a detail from the passage; the author is interested in explaining rainbows, not the refraction of light.

Finally, (E)  only addresses the last two paragraphs and is not the purpose of the passage as a whole.

Answer: B

Hope it helps

Sajjad1994 · Answer

Official Explanation

5. It can be inferred that the author of the passage would most likely agree with which of the following statements about the study of rainbows?

Difficulty Level:   Hard

Explanation

STEP 1: ANALYZE THE QUESTION STEM

This is an Inference question, asking for the statement with which the author would most likely agree.

STEP 2: RESEARCH THE RELEVANT TEXT

Since most of the passage is about the study of rainbows, review the passage map to have the structure of the passage fresh in your mind as you review the answer choices. Plan to research each choice as needed to accept or eliminate it.

STEP 3: MAKE A PREDICTION

No precise prediction of the correct answer is possible here. However, based on the passage map, you know that humans have observed rainbows for a long time and come up with various ideas about them, at least two medieval scholars conducted scientific experiments to understand rainbows, and modern physics—which explains rainbows in terms of light wavelengths and their refraction—validates the medieval research. The correct answer will align with one or more of these key ideas.

STEP 4: EVALUATE THE ANSWER CHOICES

(A)  is supported by the passage and is correct. Fourteenth-century science is first mentioned in the first paragraph and elaborated on in the second. Then, at the beginning of the third paragraph, the author says that modern physics has shown the findings of Theodoric and al-Farisi to be accurate. Thus, the author would agree that some experiments performed hundreds of years ago produced accurate results.

(B)  can be researched in the first paragraph, where such cultures are discussed. While some of the ideas seem unscientific, the author never says that such peoples did not approve of scientific studies.

(C)  is not supported. The passage only discusses these researchers’ work with water droplets, so whether they studied larger volumes of water is unknown.

(D)  is similar to  (B)  in that the author never implies that a scientific understanding of rainbows voids a belief in their spiritual significance.

(E)  is a 180. The author specifically mentions the accuracy of Theodoric and al Farisi’s work, thereby implying its value.

Answer: A

Hope it helps

VerbalBot · Answer

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Rainbows have long been a part of religion and mythology in cultures a

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