NBEO Physiological Optics Practice Test

Unlock all questions

This demo includes only 20 questions. Upgrade to access hundreds of questions, flashcards, exam simulations, and disable ads.

Full question bankExam simulationsFlashcards

From $12.50Unlock all

Session length

1 / 20

What is the approximate index of refraction and abbe value for Ophthalmic crown glass?

n=1.523, abbe=58.9

Ophthalmic crown glass has a refractive index in the low 1.5 range and a high Abbe number, meaning it bends light moderately but shows relatively little chromatic dispersion. The typical values are about n ≈ 1.523 and Abbe ≈ 58–59, which is why the match of n = 1.523 and Abbe = 58.9 is the best choice. This low-to-moderate index with high Abbe number distinguishes crown glass from materials with high dispersion (lower Abbe) or significantly different indices.

n=1.498, abbe=58

n=1.586, abbe=30

n=1.53, abbe=44