Question

The angle between the paraxial rays and principal axis is

• A. 45°
• B. 0°
• C. 90°
• D. 83°

Answer 1

The Correct Option is B

Step 1: Understand the definition of paraxial rays.

Paraxial rays are light rays that travel very close to the principal axis of an optical system and make very small angles with it. By definition, the angle between paraxial rays and the principal axis is approximately \( 0^\circ \).

Step 2: Analyze the options.

• (1) 45°: This is incorrect because paraxial rays do not make such a large angle with the principal axis.
• (2) 0°: This is correct because paraxial rays are nearly parallel to the principal axis.
• (3) 90°: This is incorrect because rays perpendicular to the principal axis are not paraxial.
• (4) 83°: This is incorrect because paraxial rays do not make such a large angle with the principal axis.

Final Answer: The angle between the paraxial rays and the principal axis is \( \mathbf{0^\circ} \), which corresponds to option \( \mathbf{(2)} \).