Spherical Mirrors
The curved surface we see of a shining spoon can be considered a curved mirror. The most widely used type of curved mirror is the spherical mirror. The reflecting surface of such mirrors is considered to form a part of the surface of any sphere. Those mirrors which possess a reflecting surfaces which are spherical, are called spherical mirrors.
There are two types of spherical mirrors for which the mirror formula is used.
Concave mirror or also called the converging mirror which have an inward bent surface. They have a negative value of focal length in sign convention and can form both virtual and real images based on the position of the object.
Position of Object | Position of Image | Image Size | Natural Image |
|---|---|---|---|
| Within focus ( Between pole P and focus F) | Behind the mirror | Enlarged | Virtual and erect |
| At focus | At infinity | Highly Enlarge | Real and Inverted |
| Between F and C | Beyond C | Enlarged | Real and Inverted |
| At C | At C | Equal to object | Real and Inverted |
| Beyond C | Between F and C | Diminished | Real and Inverted |
| At Infinity | At focus | Highly diminished (Pointed Size) | Real and Inverted |
Convex mirror or also called the diverging mirror has a bulged outward surface. They have a positive value of focal length from sign convention. They can only form virtual and erect images which can be enlarged or diminished depending on the position of the object placed.
Position of object | Position of image | Image size | Nature of Image |
|---|---|---|---|
| Anywhere between pole P and Infinity | Behind the mirror between P and F | Diminished | Virtual and erect |
| At infinity | Behind the mirror at Focus | Highly diminished | Virtual and erect |
Mirror Formula and Magnification
The light gets reflected or refracted from the surfaces or medium. Any surface which is polished or in other words shiny always acts like a mirror be it of any kind. The observation of light bouncing off or getting back from the surfaces is termed as reflection. The light after the case of reflection travels or follows in the same medium from where the ray was incident on the surface. This phenomenon of reflection does not intend to change the velocity of light it only reverses the direction of light incident on it. This can be observed on any surface which is rough or smooth. The path of the reflected ray will depend upon the extent of smoothness of the surface, in the case of a smooth surface the reflected ray emerges with the same angle as of incidence and in the latter case suffers irregular reflection and so the reflected ray doesn’t emerge same as that of incidence angle. On the other view, light can also change its speed when traveling from one medium to another which is known as refraction of light.
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