Check sibling questions

For a Convex Mirror,

The focus and center of curvature is on the right side of the mirror

So, there will only be 2 cases.


They are

  • Object is Placed at Infinity
  • Object is Placed between Principal axis and Infinity


Case 1 - Object is Placed at infinity



In this Case, Object AB is kept far away from mirror (almost at infinite distance)

So, we draw rays parallel to principal axis


Since ray parallel to principal axis appear to pass through the Focus

All rays appear to meet at focus after reflection


Hence, Image is formed at Focus

And it is on the other side of the mirror. So, Image is virtual

And it is very very small


We can say that

  • Image is behind the Mirror (Virtual Image)
  • Image is Erect
  • Image is Smaller than the Object (Highly Diminished)


Case 2 - Object is between Infinity and Pole (P)


Here, Object AB kept anywhere on the principal axis - between Infinity and Pole (P)


First, we draw a ray parallel to principal axis

So, it appears to pass through focus after reflection


We draw another ray which passes through Center of Curvature

So, the ray will go back along the same path after reflection

Where both reflected rays meet is point A'

And the image formed is A'B'

This image is formed between Pole (P) and Focus (F)


We can say that

  • Image is behind the Mirror (Virtual Image)
  • Image is Erect
  • Image is Smaller than the Object (Diminished)


To summarise

Position of the object Position of the image Size of the image Nature of the image
At infinity  At the focus F,
behind the mirror 
Highly diminished,
Virtual and erect
Between infinity
and the pole P of
the mirror
Between P and F,
behind the mirror
Diminished  Virtual and erect




NCERT Question 3 - Where should an object be placed in front of a convex lens to get a real image of the size of the object?

(a) At the principal focus of the lens

(b) At twice the focal length

(c) At infinity

(d) Between the optical centre of the lens and its principal focus.

View Answer


NCERT Question 5 - No matter how far you stand from a mirror, your image appears erect. The mirror is likely to be

(a) only plane.

(b) only concave.

(c) only convex.

(d) either plane or convex

View Answer


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CA Maninder Singh is a Chartered Accountant for the past 13 years and a teacher from the past 17 years. He teaches Science, Economics, Accounting and English at Teachoo