optical instrument physics class 12th

Summary of Optical Instruments




Optical instruments are devices that process light to enhance images or observe objects that may

not be visible to the naked eye. These instruments use lenses, mirrors, prisms, and other optical

elements to manipulate light.



1. Human Eye

- Structure:

- Cornea: Refracts light entering the eye.

- Lens: Focuses light onto the retina.

- Retina: Converts light into electrical signals.

- Iris: Controls the amount of light entering the eye.

- Working:

- Light enters through the cornea and lens, which focus it onto the retina to form an inverted image.

- The brain processes this information to perceive an upright image.



2. Microscope

- Types:

1. Simple Microscope:

- A single convex lens used for magnification.

- Used for observing small objects like insects or stamps.

2. Compound Microscope:

- Uses two lenses (objective and eyepiece) for higher magnification.

- Magnification is the product of the powers of the two lenses.

- Applications: Used in biology and material sciences to study tiny objects like cells or bacteria.