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Difficulty: MediumSingle-Sentence Inferences

Read the following excerpt from an academic history of nineteenth-century astrophysics:

"Although Gustav Kirchhoff’s 1859 formulation of spectral analysis enabled astronomers to identify chemical elements in the solar atmosphere, it was not until the development of gelatin-silver bromide photographic plates in the late 1870s that solar spectrographs could record spectral line shifts faint enough to verify Doppler-effect measurements of solar rotation."

True or False: Prior to the late 1870s, astronomers could identify chemical elements in the solar atmosphere using spectral analysis, but solar spectrographs lacked the sensitivity required to record line shifts subtle enough to verify Doppler-effect measurements of solar rotation.

Answer: Answer

Answer

True
The statement is correct because the single sentence establishes a clear chronological split: element identification was available following 1859, whereas recording faint spectral line shifts to confirm Doppler rotation measurements remained beyond spectrographic capabilities until the late 1870s development of gelatin-silver bromide plates.

Step-by-Step Solution

1
Identify the capabilities established prior to the late 1870s from the passage.
Chemical element identification in the solar atmosphere became possible starting in 1859.
The introductory clause 'Although Gustav Kirchhoff's 1859 formulation... enabled astronomers to identify chemical elements' confirms this capability existed well before the late 1870s.
2
Determine the limitation that persisted until the late 1870s innovation.
Solar spectrographs could not record spectral line shifts faint enough to verify Doppler measurements until gelatin-silver bromide plates were developed in the late 1870s.
The temporal structure 'it was not until... late 1870s that...' logically implies that recording such faint line shifts was unattainable prior to that development.
3
Compare the deduced facts against the statement.
The statement accurately presents both the achieved capability (element identification) and the existing limitation (inability to record subtle line shifts for Doppler verification) prior to the late 1870s.
Both clauses of the statement directly correspond to the logical deductions drawn from the target sentence.

Key Concept

Single-Sentence Inferences through logical parsing of contrastive conjunctions ('although') and conditional time boundaries ('it was not until').
Estimated Time:1m 30s
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Topics

Single-Sentence Inferences

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