A broken shard of glass found in the laboratory of the famed physicist Alhazen has a polished surface that separates out the green and blue spectrums of white light, a key characteristic of a dispersive prism, which separates white light into all its constituent spectral components. Scientific historians, based on this finding, are revising their histories in order to give Alhazen, the "father of modern optics", credit for the discovery of the dispersive prism, which was thought to have been discovered many years later.
Which of the following, if true, most strongly supports the historians' decision to revise the history of optics?
(A) Dispersive prisms were the only type of prism that was theorized about in the scientific era in which Alhazen lived.
(B) The piece of glass from which the shard broke, if unbroken, would have been just large enough to separate out the entire spectrum of white light into its spectral components.
(C) The piece of glass was a combination of flint glass, which was known to have been used by Alhazen to craft lenses in his laboratory, and crown glass, another popular type of glass throughout history.
(D) Dispersive prisms are the simplest and most common objects that are able to divide white light into its constituent spectral components.
(E) Several glass objects that are known to have some properties of a dispersive prism have been found to be older than the glass piece in Alhazen's laboratory.
OA: B
Source: Knewton
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a broken shard of glass
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komal
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rahul.s wrote:A broken shard of glass found in the laboratory of the famed physicist Alhazen has a polished surface that separates out the green and blue spectrums of white light, a key characteristic of a dispersive prism, which separates white light into all its constituent spectral components. Scientific historians, based on this finding, are revising their histories in order to give Alhazen, the "father of modern optics", credit for the discovery of the dispersive prism, which was thought to have been discovered many years later.
Which of the following, if true, most strongly supports the historians' decision to revise the history of optics?
Premise : broken piece of glass was found in Alhazen's lab
it had polished surface just like dispersive prism
therefore.... historians want to give him credit for the discovery of dispersive prism
(A) Dispersive prisms were the only type of prism that was theorized about in the scientific era in which Alhazen lived.
Incorrect : This does not support the conclusion that Alhazen discovered dispersive prism
(B) The piece of glass from which the shard broke, if unbroken, would have been just large enough to separate out the entire spectrum of white light into its spectral components.
Correct : This fills the gap in the argument that the piece actually belonged to dispersive prism and not something else.
(C) The piece of glass was a combination of flint glass, which was known to have been used by Alhazen to craft lenses in his laboratory, and crown glass, another popular type of glass throughout history.
Incorrect : This only weakens the conclusion that the piece of glass was some other kind of glass but not dispersive prism glass.
(D) Dispersive prisms are the simplest and most common objects that are able to divide white light into its constituent spectral components.
Incorrect : Type of dispersive prisms is irrelevant here.
(E) Several glass objects that are known to have some properties of a dispersive prism have been found to be older than the glass piece in Alhazen's laboratory.
Incorrect : Weakens the conclusion by implying that this shard of glass was not a piece of dispersive prism after all.
OA: B
Source: Knewton
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fibbonnaci
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Hey u will bang rite on the answer choice if you use the rogue element approach.
Look carefully at the premise- the glass separates green and blue light from white light
and the conclusion says historians want to give Alhazen the title of father of modern optics for discovering dispersive prism.
Now what is dispersive prism. It separated white light into its constituent parts.
But our glass piece does only green and blue light.
So we need an option that talks about how the glass piece does not only green and blue but also other constituents of light.
(A) Dispersive prisms were the only type of prism that was theorized about in the scientific era in which Alhazen lived.[ Let them be theorized. we are talking about dispersive prism and anointing them to Alhazen. Eliminated!]
(B) The piece of glass from which the shard broke, if unbroken, would have been just large enough to separate out the entire spectrum of white light into its spectral components.[ Bingo! this explains that the whole sheet of glass acts as a dispersive prism breaking the white light into its constituent parts. Correct!]
(C) The piece of glass was a combination of flint glass, which was known to have been used by Alhazen to craft lenses in his laboratory, and crown glass, another popular type of glass throughout history.[ let it contain any other material also, does that affect our reasoning? does it say how they can generalize from just green and blue light to talk about dispersive prism? Eliminated!]
(D) Dispersive prisms are the simplest and most common objects that are able to divide white light into its constituent spectral components. [ woww now let be simplest. does it matter to us? we know that dispersive prism divide white light into its parts but how does alhazen's green and blue light compete for dispersive prism? Eliminated!]
(E) Several glass objects that are known to have some properties of a dispersive prism have been found to be older than the glass piece in Alhazen’s laboratory. [This weakens the conclusion. It means to say that there must have been some other discoverer before Alhazen to whom this dispersive prism must be attributed to. Eliminated!]
Hope this helps!
Look carefully at the premise- the glass separates green and blue light from white light
and the conclusion says historians want to give Alhazen the title of father of modern optics for discovering dispersive prism.
Now what is dispersive prism. It separated white light into its constituent parts.
But our glass piece does only green and blue light.
So we need an option that talks about how the glass piece does not only green and blue but also other constituents of light.
(A) Dispersive prisms were the only type of prism that was theorized about in the scientific era in which Alhazen lived.[ Let them be theorized. we are talking about dispersive prism and anointing them to Alhazen. Eliminated!]
(B) The piece of glass from which the shard broke, if unbroken, would have been just large enough to separate out the entire spectrum of white light into its spectral components.[ Bingo! this explains that the whole sheet of glass acts as a dispersive prism breaking the white light into its constituent parts. Correct!]
(C) The piece of glass was a combination of flint glass, which was known to have been used by Alhazen to craft lenses in his laboratory, and crown glass, another popular type of glass throughout history.[ let it contain any other material also, does that affect our reasoning? does it say how they can generalize from just green and blue light to talk about dispersive prism? Eliminated!]
(D) Dispersive prisms are the simplest and most common objects that are able to divide white light into its constituent spectral components. [ woww now let be simplest. does it matter to us? we know that dispersive prism divide white light into its parts but how does alhazen's green and blue light compete for dispersive prism? Eliminated!]
(E) Several glass objects that are known to have some properties of a dispersive prism have been found to be older than the glass piece in Alhazen’s laboratory. [This weakens the conclusion. It means to say that there must have been some other discoverer before Alhazen to whom this dispersive prism must be attributed to. Eliminated!]
Hope this helps!
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rahul.s
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interesting. could you elaborate on this approach a lil more?fibbonnaci wrote:Hey u will bang rite on the answer choice if you use the rogue element approach.
Look carefully at the premise- the glass separates green and blue light from white light
and the conclusion says historians want to give Alhazen the title of father of modern optics for discovering dispersive prism.
Now what is dispersive prism. It separated white light into its constituent parts.
But our glass piece does only green and blue light.
So we need an option that talks about how the glass piece does not only green and blue but also other constituents of light.
