NCERT Solutions of Light - Reflection and Refraction Class 10
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Light: Reflection and Refraction

Formation of Image by a concave mirror:-

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 between infinity and 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)

(a) 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.

Concave mirror - object at infinity

Position of image : At F (Principal focus)

Properties of image:-

  • Point sized
  • Highly diminished
  • Real and inverted.

(b) Object between infinity and 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).

Concave mirror - object between infinity and C

Position of image:- Between C (centre of curvature) and F (Principal focus)

Properties of image:-

  • Diminished compare to object,
  • Real
  • 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.

Concave mirror - object at Centre of curvature

Position of image: At C (centre of curvature)

Properties of image:

  • Same size of object.
  • Real
  • Inverted
(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).

Concave mirror - object between C and F

Position of image: Beyond centre of curvature (C)

Properties of image:

  • Larger than object
  • Real
  • Inverted

(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.

Concave mirror - object at Principal Focus

Position of image: At infinity

Properties of image:

  • Highly enlarged
  • Real
  • Inverted

(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.

Concave mirror - object between Principal Focus and Pole

Position of image: Behind the mirror.

Properties of image:

  • Enlarged
  • Virtual
  • Erect
Concave Mirror - Image Formation
         
NCERT Solutions of Light - Reflection and Refraction Class 10
<< Reflection of rays from a spherical mirrorFormation of image by a convex mirror >>

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