PrepTest 115, Section 3, Question 17
With the approach of the twentieth century, the(454 more words not shown)
Which one of the following(9 more words not shown)
- AIf classical wave(23 more words not shown)
- BClassical wave theory,(26 more words not shown)
- CPlanck's new model(24 more words not shown)
- DPrompted by new(27 more words not shown)
- EAt the turn(35 more words not shown)
Reading the passage
We've already predicted the main point: a conflict between experimental results and wave theory helped scientists develop a better understanding of radiation. Planck changes an assumption to fit the results, and Einstein and others provide later support.
What we’re looking for
We're looking for that development, not just the initial problem or one reaction to Planck.
Working the answers
- A
Blackbody experiments matter, but this claims the ideas would never have developed without them. The account tells us what happened; it doesn't establish that no other route to these insights was possible.
- B
This gives Planck the wrong role. His hypothesis accounts for earlier experimental results. Einstein later proposes radiation as particles and finds confirming evidence. B instead credits Planck with experiments demonstrating particles.
- C
The community's initial criticism is one part of the story. Making its slow acceptance the main point leaves out the central development: a troublesome observation prompts a new, better-supported account.
- DCorrect
This keeps the sequence we predicted: new findings, Planck's rejection of the smooth-energy assumption, a hypothesis whose numbers matched the previous experimental findings exactly (paragraph 3), and later theoretical justification.
- E
Planck doesn't simply reverse the relationship between wavelength and energy. He rejects the smooth continuum in favor of discrete energy values. E misstates the change that resolves the problem.
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