Questions are based on the following passage:

The human eye is the organ that reacts to light. The outer layer of the eye is called the cornea. The cornea has a refractive index (n) of 1.38 and a radius of curvature (R) of 7.8 mm. Air has a refractive index of 1.00, while water has a refractive index of 1.33. The average distance from the cornea to the retina is 17.0 mm. Myopia, or nearsightedness, occurs when rays are focused before they reach the retina, while hyperopia, or farsightedness, occurs when light rays focus behind the retina rather than directly on it.

MCAT Chemical and Physical Foundations of Biological Systems 6

Time left 00:00

4 Questions

1. A ray of light passes from the open air into the cornea at an incident angle of 80.0°. From Snell's Law, what is the angle of refraction in the cornea?

80.0°10.0°44.5°45.5°

2. Based on Figure 1 and the information in the passage, which of the following is a possible cause of myopia?

The eye is too long.There are defects in the retinal ganglia.There is insufficient optical (refractive) power.The refractive index of the cornea constantly fluctuates.

3. What percentage of its refracting power does the cornea lose when submerged in water compared to the open air?

25%13%75%87%

4. What is the effective focal length, f, for the average eye for an object that is positioned 1.00 meter away in the open air?

1.67 mm0.0598 mm16.7 mm0.598 mm