ABO NOCE Basic Opticianry Ophthalmic Optics and Principles Questions and Answers 2

Question 1

A lens has a power of +2.50 D. What is its focal length in meters?

Accepted Answer

0.40 m

Answer

Focal length = 1 / Power, so 1 / 2.50 = 0.40 meters.

Question 2

Which type of aberration causes light rays at different distances from the optical axis to focus at different points, resulting in a blurred image?

Accepted Answer

Spherical aberration

Answer

Spherical aberration occurs when peripheral rays focus at a different point than paraxial rays due to the curvature of the lens.

Question 3

What is the index of refraction of a material if light travels through it at 2.0 × 10⁸ m/s (speed of light in air = 3.0 × 10⁸ m/s)?

Accepted Answer

1.50

Answer

Index of refraction n = speed of light in air / speed of light in medium = 3.0/2.0 = 1.50.

Question 4

A prism displaces an image toward which direction relative to its base?

Accepted Answer

Toward the apex

Answer

Light is refracted toward the base of a prism, so the image appears displaced toward the apex.

Question 5

When light passes from a denser medium to a less dense medium at an angle exceeding the critical angle, what occurs?

Accepted Answer

Total internal reflection

Answer

Total internal reflection occurs when light exceeds the critical angle at the boundary between a denser and less dense medium.

ABO NOCE Basic Opticianry Practice Test