Optics Grade 10

• Refraction ;) :

  The bending of light as it travels from one medium into another (different) medium
• Index of refraction: 

  the index of refraction is really measuring the slowing of the speed of light use the following formula where 

  n = index of refraction 

  c = speed of light (no units)

  v = speed of light (in the medium)
• partial reflection and refraction: refraction is often accompanied by reflection. 

  or 

  A BEAM IF LIGHT THAT REFLECTS AND REFRACTS AT THE BOUNDARY BETWEEN TWO MATERIALS IS SAID TO UNDERGO PARTIAL REFLECTION AND REFRACTION

  e.g. light striking down water
• total internal reflection:

  when light passes from a more dense into a less dense medium, the angle of refraction is larger than the angle of incidence
• phenomena related to refraction: Apparent depth - A pencil under water appears bent due to refraction and brain projection of light rays, creating a virtual image of the pencil tip at a shallower depth than it actually is.
• Mirage -  A mirage occurs when light moves from cool to warmer air, bending further away from normal, leading to total internal reflection in the hottest air layer.
• Shimmering - Shimmering on a lake is caused by light travelling at slightly different speeds through air layers of different temperatures, resulting in multiple virtual images on the water's surface due to total internal reflection
• flattened sun - because of refraction, sunsets present a rate chance to view an interact image, people observe that the sun appears flattened when it is close to the horizon at sunset. 
• rainbows - an optical phenomenon created by water droplets in Earth's atmosphere, forming a virtual image of the spectrum when the Sun is behind us.
• Cornea: Transparent outer layer covering the front of the eye that helps in focusing light onto the lens.
• Pupil: The black circular opening in the center of the iris that regulates the amount of light entering the eye.
• Iris: Colored part of the eye that controls the size of the pupil and thus the amount of light entering the eye.
• Lens: Transparent, flexible structure located behind the iris that helps to further focus light onto the retina.
• Retina: Innermost layer at the back of the eye that contains light-sensitive cells (rods and cones) that convert light into nerve signals.
• Rods and Cones: Rods are responsible for low-light vision, while cones are responsible for color vision and detail.
• Optic Nerve: Bundle of nerve fibers carrying visual information from the retina to the brain.
• Ciliary Muscles: Muscles around the lens that control its shape and adjust the lens to focus on objects at different distances (accommodation).
• Aqueous and Vitreous Humor: Aqueous humor is a watery fluid in the front part of the eye, while vitreous humor is a gel-like substance in the back part of the eye, both helping to maintain the eye’s shape and provide nutrients.
• Sclera: Tough, white outer layer of the eye that maintains the eye’s structural integrity.
• Reflection: The bouncing back of light when it strikes a surface.
• Incident Ray: The incoming ray of light that strikes a surface.
• Reflected Ray: The ray of light that bounces off a surface.
• Normal: An imaginary line perpendicular to the reflecting surface at the point of incidence.
• The angle of incidence is measured with respect to the normal.
• Angle of Incidence: The angle between the incident ray and the normal.
• Angle of Reflection: The angle between the reflected ray and the normal.
• Law of Reflection: States that the angle of incidence is equal to the angle of reflection. Mathematically, θi = θr.
• Plane Mirror: Flat, smooth mirrors that reflect light according to the laws of reflection.
• Images formed in plane mirrors are virtual, upright, and laterally inverted.
• Virtual Image: An image that appears to be formed behind the mirror but doesn’t actually exist.
• Real Image: An image formed by converging rays of light, typically formed by curved mirrors.
• Real images can be projected onto a screen.
• Convex mirrors are curved outward, like the back of a spoon, with a reflective surface on the outer side of the curve.
• Convex mirrors are curved outward, like the back of a spoon, with a reflective surface on the outer side of the curve.
• Convex mirrors have a virtual focal point and focal length, as the rays appear to diverge from a point behind the mirror.
• Convex mirrors have a virtual focal point and focal length, as the rays appear to diverge from a point behind the mirror.
• The principal focus of a convex mirror is a virtual point from which diverging rays appear to come.
• The principal focus of a convex mirror is a virtual point from which diverging rays appear to come.
• Convex mirrors always form virtual, upright, and diminished images.
• The image of an object is formed on the same side as the object when using a convex mirror.