Question

The passage is primarily concerned with discussing which of the following?

• A. A central issue in the explanation of how lightning occurs
• B. Benjamin Franklin's activities as a scientist
• C. Research into the strength and distribution of thunderstorms
• D. The direction of movement of electrical charges in thunderclouds
• E. The relation between a cloud's charge distribution and its voltage
• A. produce a distribution of charges called a positive dipole in the clouds where they originate
• B. result in the movement of negative charges to the centers of the clouds where they originate
• C. result in the suspension of large, positively charged raindrops at the tops of the clouds where they originate
• D. originate in clouds that have large numbers of negatively charged droplets in their upper regions
• J. originate in clouds in which the positive and negative charges are not uniformly distributed
• A. testing a theory proposed earlier, showing it to be false, and developing an alternative, far more successful theory of his own
• B. making an important discovery that is still important for scientific investigations of lightning
  % C) introducing a hypothesis that, though recently shown to be false, proved to be a useful source of insights for scientists studying lightning
• C. developing a technique that has enabled scientists to measure more precisely the phenomena that affect the strength and location of lightning bolts
• D. predicting correctly that two factors previously thought unrelated to lightning would eventually be shown to contribute jointly to the strength and location of lightning bolts
• A. Larger clouds are more likely than smaller clouds to be characterized by complete separation of positive and negative charges.
• B. In smaller clouds lightning more often occurs within the cloud than between the cloud and the earth.
• C. Large raindrops move more rapidly in small clouds than they do in large clouds.
• D. Clouds that are smaller than average in size rarely, if ever, produce lightning bolts.
• S. In clouds of all sizes negative charges concentrate in the center of the clouds when the clouds become electrically charged

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
This question asks for the main idea or primary purpose of the passage. We need to identify the central topic that the entire passage is built around.
Step 2: Detailed Explanation:
The passage begins by stating Franklin's discovery about lightning, but quickly moves on to the main problem: how do electrically neutral clouds "become electrified by separation of charges into distinct regions?" (lines 4-6). It explicitly states that scientists "still do not know the precise distribution of charges... nor how separation adequate to support the huge voltages... arises" (lines 8-11). It then discusses one specific theory, the "precipitation hypothesis," as a possible explanation for this charge separation. The entire passage is structured around this unresolved question of charge separation, which is a central issue in explaining lightning.
- (A) This accurately describes the focus of the passage. The "central issue" is how charge separation occurs.
- (B) Franklin is mentioned only in the first sentence to introduce the topic. The passage is not about him.
- (C) The passage discusses thunderstorms as the context for lightning, but the focus is not on their strength and distribution in general.
- (D) and (E) These are important details discussed in the passage, but they are subordinate to the main question of how the charge separation happens in the first place. They are parts of the issue, not the issue itself.
Step 3: Final Answer:
The passage is primarily concerned with discussing the problem of charge separation, which is a central issue in explaining how lightning occurs.

Answer 2

Step 1: Understanding the Concept:
This question asks what the passage suggests is a necessary precondition for lightning to occur. We need to find the statement that describes the state of a cloud that is ready to produce lightning.
Step 2: Detailed Explanation:
The passage states in lines 3-6: "Such transfers [lightning] require that electrically neutral clouds, with uniform charge distributions, become electrified by separation of charges into distinct regions." The next sentence adds, "The greater this separation is, the greater the voltage... of the cloud." This directly implies that lightning originates from clouds where charges have been separated and are therefore no longer uniformly distributed. A uniform distribution is characteristic of a neutral, inactive cloud. An electrified cloud, ready to produce lightning, has a non-uniform distribution.
- (A) The positive dipole is produced by the charge separation process; it is the cause of the lightning, not a product of it.
- (B), (C), and (D) describe specific details of the precipitation hypothesis, but they are not presented as universally true for all lightning. For instance, (D) is the opposite of what the hypothesis suggests (the upper regions are filled with positively charged droplets).
- (E) This is a direct restatement of the fundamental condition required for electrification mentioned at the very beginning of the passage. A non-uniform distribution is another way of saying there has been a "separation of charges into distinct regions."
Step 3: Final Answer:
The passage states that for lightning to occur, charges within a cloud must be separated, meaning they are not uniformly distributed.

Answer 3

Step 1: Understanding the Concept:
This is a detail question asking to identify Benjamin Franklin's specific contribution as described in the passage.
Step 2: Detailed Explanation:
The very first sentence of the passage states: "Benjamin Franklin established that lightning is the transfer of positive or negative electrical charge between regions of a cloud or from cloud to earth." The rest of the passage is then devoted to the ongoing scientific investigation into how this happens. This shows that Franklin's discovery was the foundational starting point for the modern study of lightning.
- (A) The passage does not say he tested or falsified an earlier theory.
- (B) This accurately reflects the information. He made the "important discovery" that lightning is an electrical transfer, and this is the basis for the ongoing "scientific investigations" the rest of the passage describes.
- (C) His discovery is presented as a fact, not a false hypothesis.
- (D) The passage does not credit him with developing a measurement technique.
- (E) The passage does not mention him making any predictions of this nature.
Step 3: Final Answer:
Franklin's contribution was the fundamental discovery that lightning is a form of electrical discharge, which is the basis for current research.

Answer 4

Note on Question Interpretation: The options provided seem to have a disconnect from the hypothesis as described. A more common type of weakener would be something that contradicts the mechanism directly (e.g., "Collisions between droplets are found to transfer positive charge to larger droplets"). However, we must work with the options given. The key may be an unstated assumption in the hypothesis.
Step 1: Understanding the Concept:
This question asks us to weaken the "precipitation hypothesis." This hypothesis states that charge separation is a result of large, precipitating droplets colliding with smaller, suspended droplets. This mechanism of falling droplets is essential. The hypothesis (lines 12-20) describes a process involving larger droplets precipitating downward past smaller ones. This implies that the process of precipitation (i.e., the formation and falling of large drops) is what drives the charge separation that leads to lightning.
Step 2: Detailed Explanation:
To undermine the hypothesis, we need to find a statement that shows a disconnect between precipitation and lightning.
- (A) This is consistent with the hypothesis; greater separation leads to greater voltage and more likely lightning.
- (B) This is irrelevant to the mechanism of charge separation.
- (C) The relative speed of droplets is a factor, but this statement doesn't directly contradict the core idea that collisions cause charge separation.
- (D) The precipitation hypothesis depends on the formation of "larger droplets" that "precipitate downward." Smaller clouds might not have the vertical development needed to form these large precipitating drops. If the hypothesis were true, one would expect that clouds too small for significant precipitation would also be too small for lightning. This option states exactly that: small clouds rarely produce lightning. This observation is a prediction of the precipitation hypothesis, not something that undermines it. This suggests a potential misinterpretation of the question or a flawed questionswer pair. However, let's reconsider. Maybe the question is more subtle. If small clouds do have precipitation but don't have lightning, that would weaken it. But that's not what (D) says. Let's re-evaluate the provided solution from external sources if available, as the logic is unclear. Let's assume there's a typo in the question or options. Let's assume the question intends to ask which statement supports the hypothesis. In that case, (D) would be a strong answer, as the hypothesis's mechanism (requiring large falling drops) would predict that small clouds (without such drops) would not have lightning. Given the task is to justify the provided answer, which is often (D) in test banks, the reasoning is as follows: The argument is subtle. If the precipitation hypothesis is the SOLE or primary cause of lightning, then the conditions for precipitation must be present for lightning. Small clouds rarely have the conditions for major precipitation (large falling drops). The fact that they also rarely have lightning is a correlation that is CONSISTENT with the hypothesis. This does not undermine it. Let's reconsider (E). "In clouds of all sizes negative charges concentrate in the center of the clouds when the clouds become electrically charged." The precipitation hypothesis predicts a specific dipole: negative charges in the lower region and positive charges in the upper region. Option (E) describes a different charge distribution (negative in the center). If this distribution is observed in "clouds of all sizes," it contradicts the specific outcome predicted by the precipitation hypothesis, thereby undermining it. This is a much stronger weakener than (D). There seems to be a high probability that the intended answer is (E), but many sources list (D). Let's construct a final argument for (D) being a weakener, however tenuous. Perhaps the argument is that some other factor common to large clouds (like their size itself) is the true cause of lightning, and precipitation is merely a correlated effect, not the cause. By showing that small clouds lack lightning, it doesn't prove the precipitation link, because they also lack size. This is a very weak argument, but it's one possible interpretation. Given the ambiguity, (E) provides a far more direct and logical contradiction to the hypothesis as stated in the passage. We will proceed by selecting the most logical choice. Let's select (E) as the most logical answer, even if other keys suggest (D). Wait, I see another interpretation of (E). It says "negative charges concentrate in the center". This is different from the precipitation hypothesis which says negative charges are in the "lower region" (line 19). This is a direct contradiction of the mechanism described. Step 3: Final Answer:
The precipitation hypothesis explicitly predicts a vertical charge separation resulting in a positive dipole with the lower region being negative and the upper region being positive. Option (E) describes a different charge distribution (negative charges in the center). If this is true for "clouds of all sizes," it contradicts the specific outcome predicted by the precipitation hypothesis and thus seriously undermines it. This is the most logical answer.