CONTENTS CONCAVE MIRROR PARTS OF CONCAVE MIRROR RULES

CONTENTS CONCAVE MIRROR PARTS OF CONCAVE MIRROR RULES FOR OBTAINING IMAGE FORMED BY CONCAVE MIRROR DIFFERENT TYPES OF IMAGES FORMED BY A CONCAVE MIRROR USES OF CONCAVE MIRRORS

CONCAVE MIRROR v A concave mirror is that spherical mirror in which the reflection of light takes place at the concave surface

PARTS OF CONCAVE MIRROR v Centre of curvature (C) v Radius of curvature (R) v Pole (P) v Principal Axis v Principal Focus (F) P <_____R___ >

RULES FOR OBTAINING IMAGES FORMED BY A CONCAVE MIRROR RULE -1 A ray of light which is parallel to the principal axis of a concave mirror , passes trough its focus after reflection from the mirror

RULE-2 A ray of light passing trough the centre of curvature of a concave mirror is reflected back along the same path

RULE-3 A ray of light passing trough the focus of a concave mirror becomes parallel to the principal axis after reflection

FORMATION OF DIFFERENT TYPES OF IMAGES BY A CONCAVE MIRROR Positions of the object : Ø between the pole (P) and focus (F) Ø At the focus (F) Ø between focus (F) and centre of curvature (C) Ø At the centre of curvature (C) Ø beyond the centre of curvature (C) Ø At infinity

WHEN THE OBJECT IS PLACE BETWEEN POLEAND FOCUS OF THE MIRROR (OBJECT BETWEEN P AND F) NATURE OF IMAGE behind the mirror v Virtual and errect v larger than the object v

WHEN THE OBJECT IS PLACED AT FOCUS OF A CONCAVE MIRROR (OBJECT AT F) NATURE OF IMAGE v at infinity v real and inverted v highly magnified or enlarged

WHEN THE OBJECT IS PLACED BETWEEN FOCUS AND CENTRE OF CURVATURE (OBJECT BETWEEN F AND C) NATURE OF IMAGE v beyond the centre of curvature v real and inverted v larger than the object

WHEN THE OBJECT IS PLACED AT THE CENTRE OF CURVATURE OF ACONCAVE MIRROR (OBJECT AT C) NATURE OF IMAGE v at the centre of curvature v real and inverted v same size as the object

WHEN THE OBJECT IS BEYOND THE CENTRE OF CURVATURE OF A CONCAVE MIRROR (OBJECT BEYOND C) NATURE OF IMAGE v v v between the focus and centre of curvature real and inverted smaller than the object

WHEN THE OBJECT IS AT INFINITY NATURE OF IMAGE v v v at the focus real and inverted much smaller than the object (or highly diminished)

USES OF CONCAVE MIRRORS Concave mirrors are used Ø As reflectors in car headlights , search lights , hand torches , and table lamps. Ø By doctors to concentrate light on body parts like ears and eyes. Ø In the field of solar energy to focus sunrays on the objects to be heated. Ø As shaving mirrors.

SUMMARISATION So far we had discussedü Concave mirrors ü Parts of concave mirrors ü Different types of images formed by a concave mirror ü Uses of concave mirror

EVALUATE YOURSELF Q 1)A ray of light which is parallel to the principal axis of a concave mirror , after reflection a) passes through its focus b) is reflected back along the same path c) becomes parallel to the principal axis d) passes through the centre of curvature

Q 2) When the object is placed at centre of curvature , then image is formed a) behind the mirror b) between focus and centre of curvature c) beyond centre of curvature d) at centre of curvature

Q 3) When the object is placed at the focus of a concave mirror, then image is formed a) behind the mirror b) at infinity c) at the focus d) beyond centre of curvature

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