Physics professor: Some scientists claim that superheated plasma in wh

Question

Physics professor: Some scientists claim that superheated plasma in which electrical resistance fails is a factor in causing so-called “ball lightning.” If this were so, then such lightning would emit intense light and, since plasma has gaslike properties, would rise in the air. However, the instances of ball lightning that I observed were of low intensity and floated horizontally before vanishing. Thus, superheated plasma with failed electrical resistance is never a factor in causing ball lightning.

The physics professor’s conclusion follows logically if which one of the following is assumed?

(A) Superheated plasma in which electrical resistance fails does not cause types of lightning other than ball lightning.

(B) The phenomena observed by the physics professor were each observed by at least one other person.

(C) Ball lightning can occur as the result of several different factors.

(D) Superheating of gaslike substances causes bright light to be emitted.

(E) All types of ball lightning have the same cause.

PyjamaScientist · Answer

Confused between D and E and still can't choose one.

Experts may opine.

Bunuel · Answer

EXPLANATION FROM Fox LSAT

The physics professor’s argument seems reasonable, except for the small fact that he has probably not seen every single instance of ball lightning in the history of the world. If he has seen every single instance of ball lightning in the history of the world, then his argument is perfectly valid. Otherwise, his argument sucks ass.

We are asked to make the professor’s conclusion “follow logically” from his facts. On a question like this, we have to find the answer that  proves  the conclusion to be true, using the evidence provided. I think the answer has to be something like, “The professor has seen every single instance of ball lightning in the history of the world.” Seriously. Without that, how can he possibly conclude, based on his own personal observations of ball lightning, that superheated plasma with failed electrical resistance is  never  a factor in creating ball lightning?

A) Not what we’re looking for. We can almost always predict the correct answer on Sufficient Assumption questions. So we shouldn’t waste time thinking about answers that don’t immediately seem to match our prediction. Let’s check all five answers first, and see if something like our prediction pops out.

B) Again, not what we’re looking for.

C) Not what we’re looking for.

D) Not what we’re looking for.

E) This is phrased somewhat differently, but it has the exact same effect as our prediction. If it is true that all types of ball lightning have the same cause, and if the professor has observed even one instance of ball lighting that was not caused by superheated plasma (which he has), then it must also be true that ball lightning is  never  caused by superheated plasma. This answer, if true, would do the same thing as our prediction. It would bridge the gap between the professor’s evidence and his conclusion. So this is our answer, and it’s simply not worth wasting time thinking about what the other answer choices might mean. This one clearly proves the conclusion of the argument to be true. The other ones don’t.

The answer is E.

unraveled · Answer

Physics professor: Some scientists claim that superheated plasma in which electrical resistance fails is a factor in causing so-called “ball lightning.” If this were so, then such lightning would emit intense light and, since plasma has gaslike properties, would rise in the air. However, the instances of ball lightning that I observed were of low intensity and floated horizontally before vanishing.  Thus, superheated plasma with failed electrical resistance is never a factor in causing ball lightning.

The physics professor’s conclusion follows logically if which one of the following is assumed?

Last sentence is the conclusion. But the sharp turn taken by the passage after the word 'however' is the most vital part of the passage. Does the professor suggests that those ball lightnings with low intensity and which floated horizontally before vanishing are representative of the all ball lightning? If so, then he/she is right in concluding in that fashion. Definitely he/she suggests so, otherwise there's no argument at all.

(A) Superheated plasma in which electrical resistance fails does not  cause types of lightning other than  ball lightning. -  WRONG. Not concerned about other types.

(B) The phenomena observed by the physics professor were each observed by at least one  other person . -  WRONG. Does that matter. No!

(C) Ball lightning can occur as the result of several different factors. -  WRONG. Yes, but it also includes superheated plasma with failed electrical resistance.

(D) Superheating of gaslike substances causes bright light to be emitted. - WRONG. Yes, true but it deviates from the core of the argument.

(E) All types of ball lightning have the same cause. -  CORRECT. Whatever the cause was of those low density ball lightning which floated horizontally before vanishing , which were observed by the professor, that cause, in general, is the reason behind ball lightning. And hence superheated plasma with failed electrical resistance can never be a factor in causing ball lightning. Perfect...!

Answer E.

Bunuel · Answer

EXPLANATION FROM POWER PREP

The physics professor argues that superheated plasma with failed electrical resistance is never a factor in causing ball lightning, because such lightning would emit intense light and rise in the air, which runs contrary to her own observations. You should expect this conclusion from the very first sentence of the stimulus: whenever the author begins by stating what "some people claim," you know that her conclusion would be the exact opposite of their argument.

To justify the professor's conclusion, you need to ensure that the instances of ball lightning that she observed are representative of  all  instances of such lightning. What if the cases she observed were not caused by superheated plasma but other cases were? To prove her conclusion, all types of lightning must have the same cause.

Answer choice (A): If superheated plasma can only cause ball lightning, the author's conclusion would be weakened. This answer choice does the exact opposite of what is needed and is incorrect.

Answer choice (B): Even if others observed the same phenomena as the professor, this would only strengthen her argument, not provide sufficient proof for it. This answer choice is incorrect.

Answer choice (C): If ball lightning can occur as a result of several different factors, then perhaps superheated plasma played no role in it. Or perhaps it did? Because the effect of this answer choice upon the argument is less than clear, it is incorrect.

Answer choice (D): That superheating gas-like substances causes bright light to be emitted is a given. You cannot justify a conclusion by repeating a premise already relied upon. This answer choice is incorrect.

Answer choice (E): This is the correct answer choice.  If all types of ball lightning have the same cause, and the instances observed by the author disprove the notion that superheated plasma played a role in them, then superheated plasma is never a factor in causing ball lightning. Do not shy away from strong language in Justify the Conclusion questions: oftentimes, the correct answer choice  must  employ strong language in order to prove the conclusion.

samarpan.g28 · Answer

The question says, conclusion will logically follow assuming what? Professor is saying phenomemons are different, that means we have to assume all phenomenons are same which causes ball lighting. Option (E) only relates.

PriChats · Answer

In case someone's confused between C, D and E

D can be eliminated straight up as it mixes the author's 2 different claims - 
 "If this were so, then such lightning would emit intense light  and ,  since  plasma has gaslike properties, would rise in the air."  
In this line, we can see that rising in the air is connected to plasma having gaslike properties. It doesn't connect to it emitting intense light. Hence, we are mixing "being gaslike" because we rise in air with "emitting intense light". I felt these were not connected. Plus, negating it attacks a claim made in premise but not the conclusion itself.

C if assumed, straight up weakens the argument's conclusion. The purpose of assumption is to make conclusions undeniably strong. Hence, rejected. Moreover, if we negate this option it doesn't weaken the conclusion.

Option E on the other hand feebly raises suspicion on the claims that "superheated plasma with failed electrical resistance is  never  a factor in causing ball lightning" as it raises a possibility that there could be a case where it  CAN  be a factor.

Hence, after getting confused between D and E I choose E over D.

Physics professor: Some scientists claim that superheated plasma in wh

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Physics professor: Some scientists claim that superheated plasma in wh

Prep Toolkit

615 to 715 in 15 Days (Ria's Strategies)

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My Rewards