PrepTest 115, Section 3, Question 23
With the approach of the twentieth century, the(454 more words not shown)
The passage is primarily concerned(1 more words not shown)
- Adiscussing the value(6 more words not shown)
- Bsummarizing the reasons(11 more words not shown)
- Cdescribing the role(8 more words not shown)
- Dexamining a critical(13 more words not shown)
- Ecomparing the various(10 more words not shown)
Reading the passage
Our main-point prediction also helps with purpose: the conflict between theory and observation leads to a better understanding of radiation. The discussion follows the problem through Planck's response and the later support. I'd look for that evolution in the theory.
Working the answers
- A
Planck's speculation is part of the story, but the writer doesn't evaluate the general worth of speculation in science. The focus is what changed in this account of radiation.
- B
This stops too soon. We hear why classical wave theory ran into trouble, then learn about the new hypothesis and its support. Rejection alone leaves out the advance that makes the ending significant.
- C
Experiments are essential here, but this is not a general discussion of their role throughout physics. It traces a particular change in theories of radiation.
- DCorrect
The physical phenomenon is radiation. The critical stage is the change from a theory whose prediction failed to a discrete-energy account supported by observations and later justification. That captures both the challenge and the progress it produced.
- E
One assumption—the smooth energy continuum—receives close attention. The writer doesn't compare the various assumptions underlying an entire scientific discipline.
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