Image Formation by Spherical Mirrors
Description:
Rules for image formation by spherical mirrors
- Rays parallel to principle axis passes through focus after reflection.
- Rays passing through focus goes parallel to principle axis after reflection.
- Rays passing through center of curvature returns on the same path after reflection.
Image formation and characteristics of image
To study image formation we place the object on the principle axis.
At least two rays coming from the object should be considered to locate an image.
We have considered three rays coming from the object −
- Ray which is parallel to the principle axis and after reflection it passes through the focus,
- Ray which passes through the focus and after reflection it becomes parallel to principle axis.
- Ray passing through the center of curvature which reflects and takes the same path.
The point of intersection of all the three reflected ray gives us the image of point A which is denoted by A`.
Point B of the image is on the principle axis so the image of point B will also be on the principle axis.
As we can observe that the object is perpendicular to principle axis, hence the image will also be perpendicular to principle axis. So when we draw a perpendicular from point ‘A`’ to principle axis we get the location of image of point ‘B’ which is denoted by B`.
Characteristics
Object location − Object is placed between infinity and center of curvature.
Image location − Image is formed between center of curvature and focus.
Size − Diminished.
Nature − As image is formed by actual intersection of rays, hence it is real.
Orientation − Image is inverted.
Nature and orientation are related to each other −
- Whenever nature of image is real then its orientation is inverted.
- Whenever nature of image is virtual then its orientation is erect.