Question

The distance between the pole and the principal focus of a spherical mirror is called:

• A. image distance
• B. object distance
• C. focal length
• D. radius of curvature

Hint:

Focal length (\(f\)) is the distance from the pole to the focus. Radius of curvature (\(R\)) is the distance from the pole to the center of curvature (\(C\)), and \(f = R/2\).

Answer 1

The Correct Option is C

Step 1: Define the relevant terms.
Pole (P): Center of the mirror's reflecting surface.
Principal Focus (F): Point where parallel rays converge or appear to diverge.
Focal Length (f): Distance between the pole and the principal focus.
Radius of Curvature (R): Radius of the sphere the mirror is part of.

Step 2: Identify the definition matching the question.
The distance between the pole and the principal focus is the focal length.