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. 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.
• D. I is a real image.

Answer 1

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

The correct options are
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 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.
D I is a real image.

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)
Optical centre (C) will be the intersection of line $AB$ and $OI$.
(C)
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.