In its search for new technologies for solar energy that can produce

The argument is that the more efficient diatom will make 'low-cost electricity' better than the current tech. The weakest link in the logic is that producing the diatom might be so expensive so as to negate any benefits from the cheaper electricity. Then this is the natural thing we need to strengthen. Other possibilities include how easy it is to sell/implement diatoms in the current system. As we know what to look for, we can just look for it, without wasting time on irrelevant info. This is a Precise approach.

(C) is the only option which does this, by saying that they are easy to make.

The plan: to investigate a new cost-effective method of developing dye-sensitive solar cells
What do we know?
- There's a new method to produce dye-sensitive cells that uses organic material.
- the passage then goes on to describe the mechanics of this efficiency

What will be useful to know in order to assess whether The plan will work?

A. Diatoms are an important link in oceanic food chains and help cycle carbon dioxide from the atmosphere.

An understanding of the importance of Diatoms to the oceanic food chains neither strengthens or weakens the decision to pursue the plan -->Eliminate (A)

B. The current cost of electricity produced by dye-sensitive solar cells is roughly three times that of non-solar electricity.
This actually presents the business case for investigating a new method of developing dye-sensitive solar cells, but it does not have any bearing whatsoever on "The plan" above.

-->Eliminate (B)

C. Because diatoms occur naturally, no special engineering processes are needed to produce the basic dye-sensitive solar cell structures.
Ok. So as a business, I don't need to invest any money or research in order to develop special engineering processes to basic start production. Good to know.

Keep

D. Dye-sensitive solar cells work somewhat more efficiently in lower light than previous solar cell technologies.
Information on the efficiency of dye-sensitive solar cells does not affect The plan at all.
Eliminate
E. The production of dye-sensitive solar cells primarily uses materials that do not harm the environment

So what? This doesn't affect the plan. It's a qualitative consideration, but it doesn't affect 'The plan' above.

Eliminate

Therefore C is correct

Hi, I believe strengthen and weaken question stems should be read carefully since many a times they also give clear instructions on what the conclusion is and what is required of the answer.
The question stem in this case says "Which of the following considerations would, if true, most strongly support the hypothesis that the plan, if implemented, will produce low-cost electricity from dye-sensitive solar cells?"
Hence it is clear that author concludes by saying that production of electricity from dye-sensitive solar cells will be low cost. We need to strengthen this conclusion.
Choice C states that no special engineering processes are needed, hence the production of electricity can be assumed to be of low cost. Best choice.
Choice D states that Dye-sensitive solar cells work somewhat more efficiently, this is already stated in the conclusion of the passage; The diatoms' structure results in more photon activity and thus more efficient production of electricity than with current dye-sensitized solar cells, which in turn lowers the cost. How will mentioning the same thing result in strengthening the conclusion?
Hope what I am saying is right!

Hello Everyone,
Though not an expert but would like to add one of the insights I saw in this question:

I think the explaination for Option D is not that its out of scope but correct reasoning is something else.
The diatoms' structure results in more photon activity and thus more efficient production of electricity than with current dye-sensitized solar cells, which in turn lowers the cost.

Remember that the currently used solar cells are also dye-sensitized. It's just the ones proposed are more optimized. Our question stem asks to strengthen the plan of implementing the new optimized dye-sensitized solar cells and we need to strengthen that part.

What option D says is -
Dye-sensitive solar cells work somewhat more efficiently in lower light than previous solar cell technologies.

It's a comparison of CURRENT ( because of the verb WORK) Dye-Sensitive solar cells to PREVIOUS solar cell technologies and thus will not strengthen the plan.

So, it's not that the option is out of scope, its just that the option strengthens the wrong part of the argument.
PS: Had it been WILL WORK and comparison would have been in future optimized dyes to the current ones then the option D would have been the correct answer.

Let me know if in any case I have thought wrongly
Regards,
Rishav

Hi varotkorn,

1. SD is working on "a new way to make" DSSCs (it is planning to use diatoms, so that's the "innovation" here), so it is likely that there are other DSSCs out there that don't use diatoms. Option D doesn't specify anything about the DSSCs that it discusses, so I'd have to say that it is talking about DSSCs in general.

2. Your first question helps us see why D is incorrect. Option D just introduces information about DSSCs in general, and gives us no reason to believe that "the (Smith-Diatom's) plan, if implemented, will produce low-cost electricity from dye-sensitive solar cells". It just says that DSSCs are somewhat better in low light conditions than previous solar tech. But how will the plan involving diatoms make electricity from DSSCs cheaper?

The correct option adds {diatoms are not likely to be expensive} to what the question says {diatoms increase the effectiveness of DSSCs}. The correct option thus gives us some reason (more than any other option) to believe that the cost of the new tech is not going to offset the efficiency gains.

The entire argument is discussing new tech for solar energy. Current tech uses some dye-sensitive solar cells. We are developing a new way to make dye-sensitive solar cells using diatoms. This will decrease the cost of generating electricity using dye-sensitive solar cells.
There is no comparison with non solar electricity in our argument. We don't need to worry about that cost. Look, there could be many factors why solar energy may be preferable. Perhaps a focus on renewable resources, perhaps some country does not have fossil fuels, perhaps to reduce pollution - whatever. Cost is not the only factor. Solar energy might be preferred because of various other reasons. We are trying to find cheaper ways while using solar energy.

Hi

It is not very clear what you mean when you say, "it does not have anything to do with the production of low-cost electricity it is more about if the plan is worth implemented or not" about option (C). Since option (C) talks about production of " dye-sensitive solar cell structures", it can only be about the cost of solar cells and hence the cost of producing electricity. Therefore, I'd say option (C) very much talks about the cost of producing electricity from solar cells.

Option (D), as you have correctly identified, is not a strong strengthener. Yes, it does talk about production of electricity in low light conditions, which may mean more electricity and hence indirectly imply lower cost. But we do not know how often these low light conditions occur and how much more efficiency we are talking about. It would be an OK choice if (C) was not present, but in the presence of (C), we should eliminate (D).

Hope this clarifies.

Can somebody explain why D is incorrect and C is correct GMATNinja


Question Stem: Which of the following considerations would, if true, most strongly support the hypothesis that the plan, if implemented, will produce low-cost electricity from dye-sensitive solar cells. (Check the highlighted portion)

If we are talking about low cost production of electricity then it means that cost of producing per unit of electricity should be low and not the cost of manufacturing the cells. Option C doesn't indicate anything about the cost of producing electricity.

Further the argument mentions that "The diatoms' structure results in more photon activity and thus more efficient production of electricity than with current dye-sensitized solar cells, which in turn lowers the cost".

Option D says that Dye-sensitive solar cells work somewhat more efficiently in lower light than previous solar cell technologies. It means that they are more efficient in producing electricity in low light and will give better electricity output than the earlier type of cells and it strengthen the argument.

SandeepS030489 :- It is because there are 2 types of Dye-sensitive solar cells - one with Diatoms and one without Diatoms. And then there are previous solar cell technologies which don't use Dye-sensitive solar cells at all.

Now option D talks about Dye-sensitive solar cells in general which would impact both with and without Diatoms Dye-sensitive solar cells and thus this comparison doesn't address the comparison we are looking for.

Hope it answers your query

The argument talks about new diatoms based dye sensitive solar cells VS current dye sensitive solar cells. Comparison is between two types of dye sensitive solar cells.
Option (D) talks about dye sensitive solar cells vs previous solar tech. This comparison is irrelevant to us so (D) is irrelevant.

Here "which" stand for "more efficient production of electricity". This usage of "which" is fine. In any case, one cannot focus on SC while working on CR/RC questions. An author will not present the best possible structure for each thought/sentence in her passage. Her focus will be on content presented in an acceptable structure, something that will get the meaning across. In SC, the best presentation (from the 5 options) of the content is important.

­Your concerns are valid, and (C) certainly does not PROVE that Smith-Diatom will be able to produce low-cost electricity from dye-sensitive solar cells. But we don't need proof -- we're only looking for the BEST answer choice. In this case, we want the answer choice that most strongly supports the hypothesis that the plan will work.

The passage talks about production of electricity using diatoms and how it would be more efficient than current methods. So if you have one system using diatoms and another using the older method, the one using diatoms will cost less to run (i.e. less money per unit of electricity created).

But what about the cost of actually building and maintaining that system? The passage doesn't talk about that at all. If you need to spend a ton of money to make the new dye-sensitive solar cells, then the savings (thanks to the improved efficiency) might not outweigh the costs.

(C) eliminates that possibility and thus strengthens the hypothesis. It's not necessarily a very satisfying OA, but it's certainly better than the other four.

I hope that helps!

DavidTutorexamPAL gmat1393 VeritasKarishma chetan2u nightblade354

Wow, an astonishing percentage of students chose D!!!




Where in the argument are we comparing the role of outside environment favoring Dye-sensitive solar cells?
Though we can bring outside info in this strengthen question, we need to stick to the scope of argument: how the mentioned
advantages of dye-sensitive solar cells can help us in producing low cost electricity than existing / previous technologies.

Dear VeritasKarishma AjiteshArun,

I have 2 questions on choice D. Please help

Choice D : Dye-sensitive solar cells work somewhat more efficiently in lower light than previous solar cell technologies.


Q1. Does Dye-sensitive solar cells in choice D. mean the new one (Smith-Diatom's plan) or the current one or both as a whole?
Note that the question stem also mentions "Dye-sensitive solar cells", which actually means the new one. However, choice D. seems to compare between 2 technologies, i.e. "Dye-sensitive solar cells" and "previous solar cell technologies". So, I am not sure how to interpret "Dye-sensitive solar cells" in choice D.

Q2. Could you please provide your explanation on why choice D. is incorrect? Is it because the passage already mentions that new dye-sensitive solar cells are "more efficient" than the current ones, so choice D. just repeats the given information. (OE does not touch upon this point).
If not, could you explain how information given in choice D. is different from that given in the passage?

Thank you in advance!

VeritasKarishma isn't B weakening the argument? If the cost of new tech is expensive, maybe it would better to use the old tech. tks!

Hello experts,
I have a question regarding this CR problem, the last part of the question asks "if implemented, will produce low-cost electricity from dye-sensitive solar cells", so we are focused on the production of low-cost electricity, answer choice C indeed, talks about costs , but it does not have anything to do with the production of low-cost electricity it is more about if the plan is worth implemented or not, on the other hand D removes the possibility that this technology might not work efficiently with lower light, I know it's not a strong strengthener but in contrast to C , it talks about the PRODUCTION of electricity aspect . Could somebody shed some light on the issue that I have, have I misunderstood the question?

In its search for new technologies for solar energy that can produce lower-cost electricity, Smith-Diatom is developing a new way to make dye-sensitive solar cells, in which photons strike light-sensitive dyes. The process uses diatoms, which are unicellular algae that have silicon shells with a complex structure. First, the organic material is removed, and then the shells are coated with a titanium dioxide film that acts as a semiconductor. The diatoms’ structure results in more photon activity and thus more efficient production of electricity than with current dye-sensitized solar cells, which in turn lowers the cost.

Which of the following considerations would, if true, most strongly support the hypothesis that the plan, if implemented, will produce low-cost electricity from dye-sensitive solar cells?

A. Diatoms are an important link in oceanic food chains and help cycle carbon dioxide from the atmosphere.
-> Irrelevant. The topic is about producing low cost electricity, not about cycle of the atmosphere.

B. The current cost of electricity produced by dye-sensitive solar cells is roughly three times that of non-solar electricity.
-> This option weakens the argument. Since the expected cost of newly developed technology is three times that of non-solar electricity, it is hard to believe that the hypothesis will produce low cost electricity in general.

C. Because diatoms occur naturally, no special engineering processes are needed to produce the basic dye-sensitive solar cell structures.
-> Correct. Option C is giving information that acquiring diatoms, which are crucial in the process of the given hypothesis, is not difficult. Thus, option C gives reason to believe that the hypothesis can be implemented.

D. Dye-sensitive solar cells work somewhat more efficiently in lower light than previous solar cell technologies.
-> Option D gives information under lower light condition. However, no information is given related to normal or higher light condition. Thus option D give merely no information in scrutinizing the argument.

E. The production of dye-sensitive solar cells primarily uses materials that do not harm the environment.
-> Irrelevant. The argument is solely focused in making lower-cost electricity not about protecting the environment.

KarishmaB - What if no special cases are not expensive, there's no proof that these are expensive in the text, we do not know that!