Question

Which of the following statements is/are true about the principal axis of a spherical mirror?

1. (i) It is normal to the mirror.
2. (ii) Point of incidence always lies on the principal axis.
3. (iii) Principal focus always lies on the principal axis

• A. 1, 2
• B. 1, 3
• C. 1 only
• D. 3 only

Answer 1

Answer:

B. 1, 3

(i).The principal axis is an imaginary line that passes through the center of curvature and the pole of the spherical mirror. This line can be considered normal to the mirror at the pole, as it is perpendicular to the tangent of the mirror at that point. So this statement is true. (iii)The principal focus of a spherical mirror is always located on the principal axis. This is true for both concave and convex mirrors, where the focus lies along this axis. this statement is true