Optics: Spherical Mirrors - PDF

# Types of spherical mirrors: - **A concave mirror (converging mirror):** - Is a mirror, whose reflecting surface is a part of the inner surface of the sphere and it converges the parallel light rays that fall on its surface. - **A convex mirror (diverging mirror):** - It is a mirror, whose...

# Types of spherical mirrors: - **A concave mirror (converging mirror):** - Is a mirror, whose reflecting surface is a part of the inner surface of the sphere and it converges the parallel light rays that fall on its surface. - **A convex mirror (diverging mirror):** - It is a mirror, whose reflecting surface is a part of the outer surface of the sphere and it diverges the parallel light rays that fall on its surface. # Concepts related to the mirrors: - **The centre of mirror curvature (C):** - It is the centre of the sphere that the mirror is considered as a part of it. - **The pole of the mirror (P):** - It is the point that lies in the middle of the reflecting surface of the mirror. - **The radius of mirror curvature (r):** - It is the radius of the sphere that the mirror is a part of it. - OR It is the distance between the centre of mirror curvature and any point on its surface. - **The principal axis of the mirror:** - It is the straight line that passes by the pole of the mirror (P) and its centre of curvature (C). - **The secondary axis of the mirror:** - It is any straight line that passes by the centre of curvature of the mirror and any point on its reflecting surface except the pole of the mirror. - **The focus of the mirror (F):** - It is the point of collection of the parallel rays (which are parallel to the principal axis) after being reflected from the mirror. - **The focal length of the mirror (f):** - It is the distance between the focus of the mirror and its pole. - **Real image:** - It is the image that can be received on a screen. - **Virtual image:** - It is the image that cannot be received on a screen. # Light reflection: - It is a phenomenon of the light bouncing off in the same medium when it strikes a reflecting surface. - **The incident light ray:** - It is the light ray that falls on the reflecting surface. - **The reflected light ray:** - It is the light ray that bounces (returns back) from the reflecting surface. - **Angle of incidence:** - It is the angle between the incident light ray and the normal. - **Angle of reflection:** - It is the angle between the reflected light ray and the normal. ## Light reflection is governed by two laws: 1. **First law:** - Angle of incidence = Angle of reflection. 2. **Second law:** - The incident light ray, the reflected light ray and the normal line to the reflecting surface at the point of incidence all lie in one plane perpendicular to the reflecting surface. # Types of mirrors: ## 1. Plane mirror: - **The properties of the image formed by a plane mirror:** - Erect - Virtual - Laterally inverted (reversed) - Image size is equal to the object in size. - The distance between the object and the mirror is equal to the distance between the image and the mirror. - The straight line joining the object to its image is perpendicular to the surface of the mirror. ## 2. Spherical mirror: - It is a mirror, whose reflecting surface is a part of a hollow sphere.