# IMAGES IN CURVED MIRRORS IMAGES IN CURVED MIRRORS

• Slides: 34

IMAGES IN CURVED MIRRORS

IMAGES IN CURVED MIRRORS • Concave mirrors are shaped like part of the inside of a sphere • Convex mirrors are shaped like part of the outside of a sphere

IMAGES IN CURVED MIRRORS Centre of sphere Concave mirror Convex mirror

The Centre of Curvature ‘C’ is the centre of the sphere of which the curved mirror forms a part. The Pole ‘P’ is the midpoint of the mirror (a. k. a. vertex) The Principal Axis is the straight line passing through the pole and the centre of curvature of a spherical mirror. The Normal at any point of a curved mirror is the straight line joining that point with the centre of curvature C of the mirror.

CONCAVE MIRRORS

CONCAVE MIRRORS • Rays of light parallel to the principal axis of a mirror, reflect through a point (in case of a concave mirror) on the principal axis. This point is the focus or focal point ‘f’ of the mirror. • A concave mirror is also known as a converging mirror • The focus is in front of the mirror. • The focus is real as the rays of light after reflection converge at the focus.

CONCAVE MIRRORS 1) A light ray parallel to the principal axis is reflected through F 2) A light ray through C is reflected back onto itself 3) A light ray through F will reflect parallel to the principle axis 4) A light ray aimed at the vertex will follow the Law of Reflection (angle of incidence = angle of reflection)

1) A light ray parallel to the principal axis is reflected through F C F

2) A light ray through C is reflected back onto itself C F

3) A light ray through F will reflect parallel to the principle axis C F

4) A light ray aimed at the vertex will follow the Law of Reflection (angle of incidence = angle of reflection) C F V

LOCATING AN IMAGE ON A CONCAVE MIRROR Only two light rays are needed to locate an image 1) A light ray parallel to the principal axis is reflected through F 2) A light ray through C is reflected back onto itself 3) A light ray through F will reflect parallel to the principle axis 4) A light ray aimed at the vertex will follow the Law of Reflection (angle of incidence = angle of reflection)

LOCATING AN IMAGE ON A CONCAVE MIRROR

LOCATING AN IMAGE ON A CONCAVE MIRROR

LOCATING AN IMAGE ON A CONCAVE MIRROR

LOCATING AN IMAGE ON A CONCAVE MIRROR Object is between F and C of a concave mirror: • the image is larger than the object • the image is inverted • the image is farther from the mirror than the object is • the image is real

LOCATING AN IMAGE ON A CONCAVE MIRROR

LOCATING AN IMAGE ON A CONCAVE MIRROR

LOCATING AN IMAGE ON A CONCAVE MIRROR

LOCATING AN IMAGE ON A CONCAVE MIRROR

LOCATING AN IMAGE ON A CONCAVE MIRROR Object is between F and the concave mirror: • the image is larger than the object • the image is upright • the image is behind the mirror • the image is virtual i. e. makeup mirrors

LOCATING AN IMAGE ON A CONCAVE MIRROR There are three regions where an object can be located: • beyond C • between C and F • between the mirror and F

CONVEX MIRRORS

CONVEX MIRRORS • In a convex mirror, rays of light (parallel to the principal axis of a mirror), appear to diverge from a point on the principal axis. This point is the focus or focal point ‘f’ of the mirror. • A convex mirror is also known as a diverging mirror • The focus is behind the mirror • The focus is virtual as the rays of light after reflection appear to come from the focus behind the mirror

CONVEX MIRRORS 1) A ray parallel to the principal axis is reflected as if it had come through F 2) A ray aimed at C is reflected back upon itself 3) A ray aimed at F is reflected parallel to the principal axis

1) A ray parallel to the principal axis is reflected as if it had come through F F C Any lines past a mirror are NOT light rays. They are represented as dotted lines.

2) A ray aimed at C is reflected back upon itself F C

3) A ray aimed at F is reflected parallel to the principal axis F C

LOCATING AN IMAGE ON A CONVEX MIRROR Only two light rays are needed to locate an image 1) A ray parallel to the principal axis is reflected as if it had come through F 2) A ray aimed at F is reflected parallel to the principal axis

LOCATING AN IMAGE ON A CONVEX MIRROR

LOCATING AN IMAGE ON A CONVEX MIRROR

LOCATING AN IMAGE ON A CONVEX MIRROR

LOCATING AN IMAGE ON A CONVEX MIRROR

LOCATING AN IMAGE ON A CONVEX MIRROR The image of an object in a convex mirror will have the following characteristics: • the image is smaller than the object • the image is upright • the image is closer to the mirror than the object is • the image is virtual The images in convex mirrors are much more similar to each other than those in concave mirrors.