FORMATION OF IMAGES IN CONCAVE MIRRORS

Formation of image depends upon the position of the object. There are six possibilities of the position of object in the case of concave mirror.

1. Object at infinity
2. Object beyond centre of curvature (C)
3. Object at centre of curvature (C)
4. Object between centre of curvature (C) and Principal focus (F)
5. Object at Principal Focus (F)
6. Object between Principal Focus (F) and Pole (P)

1. Object at infinity

Since parallel rays coming from the object converge at principal focus, F of a concave mirror; after reflection. Hence, when the object is at infinity the image will form at F.

Features of image:

• Real
• Highly diminished
• Inverted

b. Object is beyond Centre of Curvature:

When object is placed between infinity and centre of curvature of a concave mirror the image is formed between centre of curvature (C) and focus (F).


                                      
                                                          
 Features of image:

• Real
• Diminished
• Inverted

c.  Object at Centre of Curvature (C):

When the object is placed at centre of curvature (C) of a concave mirror, a real and inverted image is formed at the same position.

Features of image:

• Real
• Inverted
• Same size

d.  Object between Centre of curvature (C) and Principal Focus (F):

When the object is placed between centre of curvature and principal focus of concave mirror, a real image is formed beyond the centre of curvature (C).

Features of image:

• Real
• Inverted
• Magnified

e.  Object at Principal Focus (F):

When the object is placed at principal focus (F) of a concave mirror, a highly enlarged image is formed at infinity.

Features of image:

• Real
• Inverted
• Magnified

f.  Object between Principal Focus (F) and Pole (P):

When the object is placed between principal focus and pole of a concave mirror, an enlarged, virtual and erect image is formed behind the mirror.

Features of image:

• Virtual
• Inverted
• Magnified

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