American Board of Ophthalmology (ABO) Practice Exam

Disable ads (and more) with a membership for a one time $2.99 payment

Prepare for the American Board of Ophthalmology Exam. Challenge yourself with flashcards and multiple-choice questions, complete with hints and explanations. Get ready for your success!

Each practice test/flash card set has 50 randomly selected questions from a bank of over 500. You'll get a new set of questions each time!

Practice this question and more.

A lens with a focal length of 0.5 meters has what power?

The correct answer is: 2D

To determine the power of a lens, you use the formula for lens power, which is defined as the inverse of the focal length in meters. The formula is: \[ \text{Power (D)} = \frac{1}{\text{Focal Length (m)}} \] In this case, the focal length of the lens is 0.5 meters. Applying the formula: \[ \text{Power (D)} = \frac{1}{0.5} = 2 \, D \] Thus, the power of the lens is 2 diopters. This means that the correct answer is indeed 2D. Power measures how strongly the lens converges or diverges light, and a lens with a power of 2D indicates it is capable of bending light rays considerably over a short focal distance.