REFLECTION OF LIGHT
FORMATION OF IMAGE BY A CONVEX MIRROR
The image formed in a convex mirror is always virtual and erect, whatever be the position of the object. Now, let’s study the types of images formed by a convex mirror
1. When the object is placed at infinity
When the object is placed at infinity, the two rays AD and BE which run parallel to the principal axis gets diverged in the directions DG and EH respectively after getting reflected from the convex mirror. When the diverged rays DG and EH are extended backwards, they intersect each other at the principal focus F.
Therefore, in convex mirror if the object is present at infinity then the image is formed behind the mirror at the principal focus, which is highly diminished, virtual and erect.
2. When the object is placed anywhere between pole and infinity
If the object is placed anywhere between the pole and infinity, a ray of light AD starting from point A of the object which run parallel to the principal axis gets reflected along DX. On producing back, DX appears to come from F. another ray AE from point A of the object which go towards the centre of curvature is reflected back along EA.
These two reflected rays i.e. DX and EA are diverging rays and appears to intersect each other at point A’ when produced back. So in this case the image is formed behind the mirror, between the pole and the principal focus, which is diminished, virtual and erect.
Table: Summary of images formed by a convex mirror
|S No.||Position of Object||Position of Image||Size of Image||Nature of Image|
|1.||At infinity||At the focus F, behind the mirror||Highly diminished||Virtual and erect|
|2.||Between infinity and the pole P||Between P and F, behind the mirror||Diminished||Virtual and erect|
Test Your Understanding and Answer These Questions:
- Explain formation of different types of images by a convex mirror with the help of diagrams.