GMAT CR|Strengthen Question|help

[Examhacker1]

A broken shard of glass found in the laboratory of the famed physicist Alhazenhas 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 Alhazenlived.

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 Alhazento 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’slaboratory.


I need help on this question. I chose A, which happens to be the wrong answer

[Clay Cooper]

Hi Examhacker1,

Thanks for your question. Generally speaking, we need a bit more input from you before we delve into a discussion of a particular LR question. Ultimately, it won't be us who are taking the test; it's you! Our goal is to help you cultivate the analytical ability to approach these questions on your own, which is why you need to help us help you first.

Here's what I'd like you to do:

• 1. Describe your approach to the stimulus. Did you understand the argument, if any, from a structural standpoint? What is the conclusion, and what evidence is the author using in support of that conclusion?
  
  2. Did you prephrase an answer to the question in the stem? If so, what was your prephrase?
  
  3. What exactly made the two answer choices you have listed particularly attractive? Did you use any question type-specific test (e.g. Assumption Negation Technique) to differentiate between them?

Thanks.

[Examhacker1]

Sure.that is a better way !
Gist:
a broken glass piece found, in physict's lab, that separates light partially.(evidence)
This is similar to dispersion as observed via dispersive prism.(link)
So, this physict can be credited with dispersive prism.(conclusion)
Prephrase: some link between glass and prisms.
No negation nor other techniques used after this.
Based on prephrasing, I was able cut down C, D, E. I was left with A and B as contenders and couldn't pick B which is right choice.

A states a link between physict's time period and prisms.
B states link between found glass and unshattered glass, probably referring to a prism.
Do we have to assume that unbroken glass as the prism ?

[Shannon Parker]

For a strengthen question you are looking for the answer choice that increases the likelihood that the stated conclusion is true.

A doesn't strengthen the argument because it doesn't connect Alhazen to the use of glass to disperse light.

C weakens the argument by showing that Alhazen had another use for the glass that wasn't light dispersion.

D neither strengthens or weakens the argument because it doesn't connect Alhazen to the use of prisms to disperse light.

E slightly weakens the argument by showing that the possibility existed before the glass in Alhazen's laboratory.

B demonstrates that the piece of glass which the shard came from was originally large enough to fully disperse light, thus making it possible that Alhazen used it for that purpose. Although it does not greatly strengthen the argument, it does strengthen it, and therefore is the correct answer.

Hope this helps.
~shannon