Image Formation by Curved Mirror

Image formation by a concave mirror:

1. When position of object is at infinity, position of image is at principle focus (F). Image is real inverted highly diminished.

2. When position of object is in between infinity and  centre of curvature (C), position of image is in between focus (F) and the centre of curvature (C). Image is real inverted  diminished.

3. When position of object is at centre of curvature (C), position of image is also at the centre of curvature (C). Image is real inverted and same size of object.

4. When position of object is in between focus (F) and the centre of curvature (C), position of image is in between centre of curvature (C) and infinity. Image is real inverted magnified.

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5. When position of object is at principle focus (F), position of image is also at Infinity. Image is real inverted and highly magnified.

6. When position of object is in between infinity and pole (P), position of image is in between focus(F) and pole (P). Image is virtual erect and diminished.

Image formation by a convex mirror:

1. When position of object is at infinity, position of image is at principle focus (F). Image is virtual erect highly diminished.

2. When position of object is in between infinity and the pole (P) of the mirror, position of image is in between pole (P) and focus (F). Image is virtual erect  diminished.

Mirror formula:

If an object is at a distance u from the pole of a mirror of focal length f, then image distance is v. The Mirror formula is .

Magnification power: The magnification is the ratio of the size (or height) of the image to the size (or height) of the object.

m = – = . Where h1 is the height of object and h2 is the height of image. For real image h2 is —ve, and m is —ve, for virtual image h2 is +ve and m is +ve.

Magnification in concave mirror (real image): Let us consider AB is an object of height h and after reflection A/B/ is the real image of the object of height h/. From figure ABP and A/B/P are similar. So, =

Or, =

Magnification m =  = – .

Magnification in concave mirror (virtual image): Let us consider AB is an object of height h and after reflection A/B/ is the virtual image of the object of height h/. From figure ABP and A/B/P are similar. So, =

Or, =

Magnification m =  = – .

Graph:

The mirror formula is  .

Let us consider  = y,  = x and  = c

Then y + x = c

Or, y = – x + c

This is equation of straight line.