Light 🔦

Light

An energy that enables us to see.

Reflection

Bouncing back of light from a surface in the same medium.

Law of Reflection

1. Angle of Incidence = Angle of Reflection; 2. Incident ray, Reflected ray & Normal lie on the same plane.

Regular Reflection

When a beam of parallel rays is incident to a smooth surface, the reflected rays are also parallel.

Diffused Reflection

When a beam of parallel rays is incident on a rough surface, the rays get reflected in different directions.

Mirror

A polished shiny surface that changes the direction of light.

Properties of Image in a Plane Mirror

Virtual and erect, laterally inverted, same size as the object, distance from object to mirror = distance from mirror to image.

Periscope

An instrument that helps see objects not in direct line of sight, commonly used in submarines.

Kaleidoscope

A device that reflects light through mirrors to form patterns.

Dispersion of Light

The separation of white light into its seven colors, forming a spectrum.

Cornea

The part of the eye where maximum bending of light occurs and protects the eye.

Pupil

The window of the eye that changes size depending on light intensity.

Iris

The colored part of the eye that controls the size of the pupil.

Lens

Part of the eye that helps in forming images.

Ciliary Muscles

Muscles that control the thickness and curvature of the lens.

Retina

The screen of the eye where the image is formed, containing rods and cones.

Optical Nerve

Transmits images formed on the retina to the brain in the form of electrical signals.

Blind Spot

The area where optical nerves bundle together, lacking photo receptors.

Nearsightedness (Myopia)

Condition where nearby objects are clear but distant objects are not.

Farsightedness

Condition where distant objects are clear but nearby objects are not.

Cataract

Condition where the eye lens becomes opaque.

Braille System

A system of reading and writing by touch, invented by Louis Braille, used by people with low vision.