Question

A luminous point object is placed at $O$, whose image is formed at $I$ as shown in figure. Line $AB$ is the optical axis. Which of the following statement is/are correct?

• A. If a lens is used to obtain the image, then it must be a diverging lens and its optical centre will be the intersection point of line $AB$ and $OI$.
• B. If a lens is used to obtain the image, then it must be a converging lens and its optical centre will be the intersection point of line $AB$ and $OI$.
• C. I is a real image.
• D. If a mirror is used to obtain the image then the mirror must be concave and object and image subtend equal angles at the pole of the mirror.

Answer 1

Answer: (B), (C), (D)

If a mirror is used to obtain the image then the mirror must be concave and object and image subtend equal angles at the pole of the mirror.

Since, the image is inverted. So, it must be real which can be obtained either by convex/ converging lens or concave- Mirror.
(A) Wrong because lens / mirror used must be of converging nature.
(B)
LensOptical centre (C) will be the intersection of line $AB$ and $OI$.
(C)
C[Pole point]From figure, $\angle OCB=\angle ICB$
(D) in both the cases, the images formed are Real due to actual meeting of Reflected light Rays.
Option B,C,D are Correct.