Optical Instruments

Human Eye

1. The human eye is a natural optical instrument that enables vision.
2. It consists of components like the cornea, lens, retina, iris, and optic nerve.
3. The lens focuses light onto the retina, where the image is formed.
4. The ability to focus on objects at varying distances is due to the process of accommodation.
5. Common defects include:
   • Myopia (short-sightedness): Corrected with concave lenses.

Lens Formula

1. The lens formula is given by 1/f = 1/v - 1/u, where:
   • f: Focal length of the lens
   • v: Image distance
   • u: Object distance
2. This formula is applicable for both convex and concave lenses.
3. The sign convention depends on the position of the object and the nature of the lens.
4. Convex lenses (converging lenses) have positive focal lengths, while concave lenses (diverging

Basics of Mirrors

1. A mirror is a reflective surface that forms images by reflecting light.
2. Plane mirrors produce upright, virtual images with the same size as the object.
3. Curved mirrors are classified as concave or convex based on the direction of curvature.

Concave Mirrors

1. A concave mirror has a reflective surface that curves inward.
2. It can produce real or virtual images depending on the object's