Which of the following depend on whether rays are paraxial or not for spherical mirrors ?

Options

A. Pole
B. Principal axis
C. Radius of curvature
D. Focus

Explanation

To determine which of the options depend on whether rays are paraxial or not for spherical mirrors, we will analyze each option step by step.

### Step 1: Understand the Definitions
- **Pole**: The pole of a spherical mirror is the center point of the mirror's aperture. It is a fixed point and does not change based on the nature of the incoming rays.
- **Principle Axis**: The principle axis is the line that connects the center of curvature and the pole of the mirror. This is also a fixed line and does not depend on the incoming rays.
- **Radius of Curvature**: The radius of curvature is the distance from the center of curvature to the pole. This value is constant for a given mirror and does not depend on the nature of the rays.
- **Focus**: The focus of a mirror is the point where parallel rays converge after reflection. This point can change depending on whether the rays are paraxial or not. If the rays are not paraxial, spherical aberration occurs, causing the rays to converge at different points rather than a single sharp focus.

### Step 2: Analyze Each Option
- **Option A: Pole** - Does not depend on whether rays are paraxial or not.
- **Option B: Principle Axis** - Does not depend on whether rays are paraxial or not.
- **Option C: Radius of Curvature** - Does not depend on whether rays are paraxial or not.
- **Option D: Focus** - Depends on whether rays are paraxial or not due to the effects of spherical aberration.

### Conclusion
The only option that depends on whether the rays are paraxial or not is **Option D: Focus**.