Question

Statement-I: As the distance x of a parallel ray from axis increases, the focal length decreases.

Statement-II: As x increases, the distance from the pole to the point of intersection of a reflected ray with the principal axis decreases.

(A) Statement-I is true, and statement-II is true; statement-II is correct explanation for statement-I.

(B) Statement-I is true, and statement-II is true; statement-II is NOT the correct explanation for statement-I.

(C) Statement-I is true, and statement-II is false.

(D) Statement-I is false, and statement-II is true.

Answer 1

The correct option is (A).

Explanation:

This phenomena is called spherical aberration. The rays close to the principal axis are focused at the geometrical focus F of the mirror as given by mirror formula. The rays farthest from the principal axis are focused at a point somewhat closer to mirror.