1. Spherical Mirrors

• Concave Mirror: A spherical mirror with a reflecting surface that curves inwards. It is a converging mirror. Uses: Torches, headlights, dentist mirrors, and solar concentrators.
• Convex Mirror: A spherical mirror with a reflecting surface that curves outwards. It is a diverging mirror. Uses: Side-view mirrors in vehicles, road safety mirrors, and surveillance mirrors.

2. Images Formed by Mirrors

• Concave Mirror: When an object is close, the image is erect and enlarged. When moved farther away, the image becomes inverted and eventually diminishes in size.
• Convex Mirror: The image formed is always erect and diminished (smaller) in size, regardless of the distance.

3. Laws of Reflection

These laws apply to all mirrors (plane and spherical):

• The angle of incidence (i) is equal to the angle of reflection (r).
• The incident ray, the normal to the mirror at the point of incidence, and the reflected ray, all lie in the same plane.

4. Lenses

• Convex Lens: Thicker in the middle than at the edges. It converges light rays. Used in magnifying glasses, cameras, and microscopes.
• Concave Lens: Thicker at the edges than in the middle. It diverges light rays. Always forms an erect and diminished image.