Q21

[tamwaiman]

I choose (D), since Plank did contribute to the classical wave theory, "So in just a few years, what was considered a catastrophe generated a new vision in physics that led to theories still in place today" (L59-61).

Although the passage mentions "the approach of the 20th century" (L1) and "the turn of the century" (L27), they indicate the time of UV catastrophe but not the blackbody radiation experiments.

Please help me, this passage is quite clear, but the answers are difficult to understand. Thanks.

[ManhattanPrepLSAT2]

Hi! I apologize if there is a typo in our practice guides (please let us know if there is!) but the correct answer to this question is (D).

Max Planck did not contribute to classical wave theory -- he came up with an alternative idea that refuted it.

In terms of the blackbody radiation -- we're told this took place in the early 20th -- it is what caused the obstacles.

Hope that helps! Please follow up if you have any additional q's.

[interestedintacos]

Have to correct you Mike (and the guide perhaps)...the author explicitly states that Planck "made important contributions to wave theory." D is correct because the passage doesn't say what contributions he made specifically, while nevertheless stating he contributed.

We have to be careful to make these points I think because sometimes test makers take advantage of test takers who make assumptions like "well the passage is about Planck coming up with new stuff refuting a classical assumption, so he couldn't have ever supported or been part of the old stuff." Sometimes focusing on the main stuff going on is enough to pick up a bunch of points. Other times questions will have a narrow focus and trick you into choosing an incorrect answer including an assumption based on the main point. I suppose they mainly test your ability to pick up on the "forest" but also test to make sure your emphasis on the forest doesn't cloud your ability to distinguish what's up with some of the "trees."

[ManhattanPrepLSAT2]

You are quite right interestedintacos! I must have been too hasty in writing that response -- thanks for the careful eye.

[jimmy902o]

I am not seeing how D can be correct. Wasn't Planck's contribution "discarding the assumption of radiation's smooth energy continuum" (lines 37-38)?

[ohthatpatrick]

Remember, in the context of this passage, that Planck enters the scene once scientists have seen that wave theory is apparently wrong/broken.

Planck "discards wave theory's assumptions" (i.e. starts fresh). The theory he ultimately comes up with "directly opposes" wave theory.

So the ideas Planck comes up with are not additions to wave theory but alternatives.

And ultimately, Planck's ideas spelled the demise for wave theory.

So while we COULD say "Planck contributed the kiss of death or final nail in the coffin for wave theory", that would be a weird stretch of "making a contribution".

Really, this question is testing our understanding that Planck was not a wave theorist; he came up with an alternative model.

=== other answers ===
A) the "ultraviolet catastrophe" described in the 2nd paragraph
B) lines 48-50
C) line 1 / line 27
E) 50-54

Hope this helps. Let me know if question remain.

[deedubbew]

For some reason, when I read lines 50-54 I thought to myself that they were looking at numbers or data and made calculations. And that experimentation was not necessarily done.

[Emmeline Ndongue]

For some reason, when I read lines 50-54 I thought to myself that they were looking at numbers or data and made calculations. And that experimentation was not necessarily done.

agree. (E) this was a tough one since it actually was Planck's hypothesis for the black body radiation "experiment" that led to Einstein's later discovery. I also want to add that, I initially read line 32-37 too fast, thinking that the important contributions meant the hypothesis. However, you quickly saw that "broke with" wave theory. It'd be a bit weird to say it's a contribution, according to patrick's earlier response.