+1 for verbal

Thank you so much, Abhishek! And thank you for all of your positivity in the comments, and for helping out other viewers with their questions. It's always lovely to have some community spirit in the wilderness of KZfaq. :)

Hi Karan, Thank you for the reminder! It's totally my fault that there weren't any links to the passages in the description for this video. I've added links to each of the passages and listed the question numbers covered at the bottom of the description. I hope that helps!

In RC, you'll see either three or four questions per passage, and each question is counted separately as one of the 23 questions on the verbal section. I hope that helps!

Absolutely I took the approach that since the conclusion mentions asteroids greater than 200m in diameter I need to find an exception and hence went to select option a based on frequency of rotation Very tough question

@GMATNinjaTutoring Isn't there an issue with this question in that the passage also mentions that the rotation speed at which pieces would fly off depends "on the asteroid's bulk density." Who is to say that 1000m once every 24 hours isn't similar to 200m once every few hours making E another viable option since we don't know the value of bulk density? I know we shouldn't get too bogged down in the details, but feels like an odd disclaimer to be in the passage if it doesn't apply to the largest asteroid in the question.

me too

Hi! The first sentence of the second paragraph is very helpful when looking at this question. This sentence tells us: "Though the extreme rapidity of quantum tunneling was noted as early as 1932, not until 1955 was it hypothesized-by Wigner and Eisenbud-that tunneling particles sometimes travel faster than light." If answer choice (D) was going to be the correct answer to this question, we'd need to be able to infer that the early researchers were "UNABLE to observe instances of successful tunneling." However, the researchers working in 1932 must have seen at least one instance of successful tunneling in order to note the "extreme rapidity of quantum tunneling." It doesn't make sense for these researchers to be noting how fast the particles can tunnel if they were unable to observe any instances of successful tunneling. For this reason, we can eliminate (D) as a potential answer to this question. Even though the early researchers were noting the "extreme rapidity" of the tunneling particles, the sentence quoted above tells us that it wasn't "until 1955" that anyone hypothesized that the particles traveled faster than light. This suggests that the early researchers working in the 1930s and 1940s did NOT think that particles were capable of faster-than-light travel, giving us enough justification to select (C) as our answer to this question. I hope that helps!

@@harryduthie Makes sense! Thank you for taking the time to reply, really appreciate it.

@@harryduthie I picked option B. My reason to reject C is- Yeah, they did notice instances of things going fast. What if they though of them as errors or they did though that perhaps particles could move faster than speed of light, it’s just that they couldn’t come up with hypotheses or evidence because of lack proof, what if they did hypothesised by we’re waiting for a concrete evidence to perhaps prove it with experiments but they couldn’t do it due to technology restrictions thus they just made public their thoughts.

The difference between (A) and (E) is that (A) talks about all asteroids and (E) talks about large asteroids. The passage told us that large asteroids are rubble piles, and these will persist after collisions for exactly the reason you provided in your comment. The reason (A) cannot be the answer is that we can't tell whether all asteroids 'will get smaller rather than larger over time'. We don't have any information about what happens to the smaller, monolithic asteroids, and we can't say the author mentions escape velocity as part of a discussion about these smaller asteroids. It's the "large" in (E) that makes a big difference between the two answer choices. I hope that helps!

Hi Shugsbunny, You're right: the third paragraph does mention the use of photons. However, we need to pay close attention to the wording of the question to make sure we're answering the question as it's asked. In this question, we're asked about the "earliest scientific investigators" of quantum tunneling. The third paragraph discusses the use of photons in "several recent experiments," so this part of the passage isn't relevant to this question. Since we can't tell what type of particles the earliest investigators of quantum tunneling used, we can cross out (E). I hope that helps!

@@harryduthie thanks for the explanation!

Hi Shriya, The earliest scientists are neither Wigner and Eisenbud nor Chiao and his colleagues. The earliest scientists aren't mentioned by name, but there's an implied reference to them at the start of the second paragraph: "Though the extreme rapidity of quantum tunneling was noted as early as 1932, not until 1955 was it hypothesized-by Wigner and Eisenbud-that tunneling particles sometimes travel faster than light." From this, we can tell that there were scientists investing quantum tunneling as early as 1932, far earlier than Wigner and Eisenbud. We don't know what particles they used in their experiments, so we can't infer that they made use of photons in their experiments. This is sufficient to eliminate (E) as a possible answer. What we can infer from this sentence is that these early investigators did not think tunneling particles could travel faster than the speed of light as it wasn't until 1955 that Wigner and Eisenbud made this hypothesis. This gives us enough information to choose (C) as the correct answer. I hope that helps!

it is an evident conclusion in para 2 hadn't reached there :O

This question asks us to consider what would happen "if tunneling time reached no maximum in increasing with barrier thickness." We have to consider what happens *when a particle is tunneling* in order to answer this question. We don't have to think about the probability a particle will or will not tunnel through a barrier because we KNOW a particle is tunneling if we're thinking about the time it takes the particle to tunnel through the barrier. The first paragraph does tell us that "the probability [that a particle will tunnel through a barrier] declines exponentially as the thickness of the barrier increases." However, this isn't relevant to this question as we're only thinking about what happens WHEN a particle tunnels through a barrier. This means we can eliminate (E). The second paragraph tells us that "the time it takes a particle to tunnel through a barrier increases with the thickness of the barrier until that time reaches a maximum; beyond that maximum, tunneling time stays the same regardless of barrier thickness." This means that we could increase the distance a particle has to travel to tunnel through a barrier and the time would remain constant. Using D = R*T, this means that the particles speed must "increase without limit as barrier thickness increases." If we remove the constraint that tunneling time reaches a maximum, then there is no requirement for the speed of the particle to "increase without limit" as the time in D = R*T could increase, rather than the speed. This is what (D) says and is the reason why (D) is the answer to this question. I hope that helps!

Hi Metal, You're right: there's a bit of reading between the lines in order to see the implication and looking back at my explanation, I think I struggled to pretend I didn't know what was coming later in the passage. In paragraph one, we're told that "If asteroids are rubble piles, however, the tail [of the bell-shaped distribution of asteroids' rotation rates] representing the fast rotators would be missing." We're then told that this tail is missing (with 5 notable but small exceptions) in the observed data. Using the author's (admittedly slightly sloppy) language, this implies that large asteroids are rubble piles. However, it might have been better if I'd said that " *the author suggests* the evidence in the first paragraph tells us large asteroids are rubble piles." This aligns with what the author says at the start of paragraph two when they give us their conclusion for this data: "asteroids larger than 200 meters across are multicomponent structures or rubble piles." I hope that helps!

@@harryduthie I understand now. Thanks Harry!

Hi @Illukaaas, While we can't put a specific level on it, this is definitely a hard passage. The GMAT Official Guide puts it in the "Hard" category, and GMAT Club rates this as a 700-Level passage. If you can do this passage comfortably, you're probably set up to do well in science based RC passages.

Same! I gave up on it in the middle. Wasn't able to wrap my head across it.

For now, six videos are planned in RC then CR will follow.

Hi Suyash, From the information in the passage, we can't tell *exactly* what the early scientists were aiming to test in their experiments, but the passage suggests they were exploring quantum tunneling and examining how particles can 'tunnel' through barriers. Scientists may now use quantum tunneling to send particles faster than the speed of light, but we can infer that the first experiments weren't necessarily designed to test the speed of the particles; they were more about getting a particle to tunnel through a barrier. The passage tells us that the scientists may have noted "the extreme rapidity of quantum tunneling" as early as 1932, but we're told that Wigner and Eisenbud were the first scientists to hypothesize that the particles traveled faster than the speed of light in 1955. From this, we can tell that the scientists measured the speed of the particle as it 'tunneled' through a barrier, but for some time they didn't consider that the particles could travel faster than the speed of light. This gives us the information we need to select (C) as the answer to this question. I hope that helps!

@@GRENinjaTutoring alright, got it. Thanks!

Hi! I'd suggest you try to do each passage in one go as much as you can. You'll notice and retain much more of the passage when you read it a second time, but you won't have the time to read the passage repeatedly in the real test. It'll be hard at first but, with practice, you should be able to get through a whole passage in one go. One of the many reasons we suggest people use LSAT RC sections to prepare for the GMAT is how long the LSAT passages are. If you keep working until you're able to do an entire LSAT RC section (4 passages with around 27 questions) in one sitting, you'll definitely have the stamina to complete the GMAT RC passages. I hope that helps!

*Photons

Hi @@strangers8882, I'm guessing you're asking about the third question associated with the first passage, but please tell me if I've got that wrong. You're absolutely right: the third paragraph does mention the use of photons. However, we need to pay close attention to the wording of the question to make sure we're answering the question as it's asked. In this question, we're asked about the "earliest scientific investigators" of quantum tunneling. The third paragraph discusses the use of photons in "several recent experiments," so this part of the passage isn't relevant to this question. Since we can't tell what type of particles the earliest investigators of quantum tunneling used, we can cross out (E). I hope that helps!