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

Convex Mirror - Object at Infinity - Ray Diagram - Teachoo.jpg

 

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)

Convex Mirror - Object at between Infinity and Pole - Teachoo.jpg

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,
point-sized
Virtual and erect
Between infinity
and the pole P of
the mirror
Between P and F,
behind the mirror
Diminished  Virtual and erect

 

 

Questions

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

 

  1. Class 10
  2. Chapter 10 Class 10 - Light - Reflection and Refraction

About the Author

Davneet Singh's photo - Teacher, Computer Engineer, Marketer
Davneet Singh
Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 9 years. He provides courses for Maths and Science at Teachoo.