Question

Any light ray passing through the principal axis of lens is \dots

• A. deviated ray
• B. undeviated ray
• C. reflected ray
• D. refracted ray

Hint:

In ray diagrams, a ray through the optical center is drawn as a straight line because it does not bend noticeably.

Answer 1

The Correct Option is B

Concept: The principal axis is the straight line passing through the optical center and centers of curvature of a lens.

Step 1: Understand the behavior of rays through optical center. A ray passing through the optical center of a thin lens emerges without deviation because refraction at the two surfaces effectively cancels out.

Step 2: Relate to principal axis. A ray traveling exactly along the principal axis passes symmetrically through the lens and therefore continues in the same direction.

Step 3: Identify the nature of the ray. Thus, such a ray is called an: \[ \boxed{\text{undeviated ray}} \] Hence, the correct option is (2).