Reflection and Refraction of Light

Definition: The bouncing back of light when it hits a surface.
Laws of Reflection:
1. The incident ray, reflected ray, and normal at the point of incidence all lie in the same plane.
2. The angle of incidence is equal to the angle of reflection.
Types of Reflection:
- Regular Reflection: Occurs on smooth surfaces; produces clear images (e.g., mirrors).
- Diffused Reflection: Occurs on rough surfaces; light scatters, producing no clear image (e.g., paper).
Applications: Mirrors (plane, concave, and convex), periscopes.

Definition: The bending of light as it passes from one medium to another due to a change in speed.
Laws of Refraction:
1. The incident ray, refracted ray, and normal all lie in the same plane.
2. The ratio of the sine of the angle of incidence to the sine of the angle of refraction is constant (Snell's Law).
Refractive Index: A measure of how much a substance can bend light; defined as the ratio of the speed of light in vacuum to the speed of light in a medium.
Types of Lenses:
- Convex Lens: Converges light rays; used in magnifying glasses and cameras.
- Concave Lens: Diverges light rays; used in eyeglasses for nearsightedness.

Definition: Devices that use lenses and mirrors to manipulate light to aid in vision.
Common Optical Instruments:
- Microscope: Uses multiple lenses to magnify small objects.
- Telescope: Used to view distant objects; can be refracting (lenses) or reflecting (mirrors).
- Camera: Captures images using a lens to focus light onto a sensor or film.
- Projector: Projects images onto a screen using lenses to enlarge the image.

Structure of the Eye:
- Cornea: The clear front surface that refracts light.
- Pupil and Iris: Controls the amount of light entering the eye.
- Lens: Focuses light onto the retina.
- Retina: Contains photoreceptors (rods and cones) that convert light into electrical signals.
- Optic Nerve: Transmits visual information to the brain.
Vision Process:
1. Light enters through the cornea and pupil.
2. The lens focuses the light onto the retina.
3. Rods detect light intensity, cones detect color.
4. Signals are sent to the brain for interpretation.
Common Defects:
- Myopia (Nearsightedness): Trouble seeing distant objects; corrected with concave lenses.
- Hyperopia (Farsightedness): Trouble seeing close objects; corrected with convex lenses.
- Astigmatism: Blurred vision due to uneven curvature of the cornea; corrected with cylindrical lenses.

Light bounces back when it hits a surface
Laws of Reflection:
- Incident ray, reflected ray, and normal all lie in the same plane
- Angle of incidence equals angle of reflection
Types of Reflection:
- Regular Reflection: Smooth surfaces, clear images (e.g., mirrors)
- Diffused Reflection: Rough surfaces, scattered light, no clear image (e.g., paper)
Applications: Mirrors (plane, concave, convex), periscopes

Light bends when passing from one medium to another due to a change in speed
Laws of Refraction:
- Incident ray, refracted ray, and normal all lie in the same plane
- Ratio of sine of angle of incidence to sine of angle of refraction is constant (Snell's Law)
Refractive Index: Measures how much a substance bends light; ratio of speed of light in vacuum to speed of light in a medium
Types of Lenses:
- Convex Lens: Converges light rays (magnifying glasses, cameras)
- Concave Lens: Diverges light rays (eyeglasses for nearsightedness)

Devices using lenses and mirrors to manipulate light for vision
Common Optical Instruments:
- Microscope: Magnifies small objects using multiple lenses
- Telescope: Views distant objects (refracting - lenses, reflecting - mirrors)
- Camera: Captures images by focusing light onto a sensor or film
- Projector: Enlarges images using lenses to project them onto a screen

Structure of the Eye:
- Cornea: Clear front surface that refracts light
- Pupil and Iris: Control light entering the eye
- Lens: Focuses light onto the retina
- Retina: Contains photoreceptors (rods and cones) converting light to electrical signals
- Optic Nerve: Transmits visual information to the brain
Vision Process:
- Light enters through cornea and pupil
- Lens focuses light onto retina
- Rods detect light intensity, cones detect color
- Signals sent to brain for interpretation
Common Defects:
- Myopia (Nearsightedness): Difficulty seeing distant objects (corrected with concave lenses)
- Hyperopia (Farsightedness): Difficulty seeing close objects (corrected with convex lenses)
- Astigmatism: Blurred vision due to uneven cornea curvature (corrected with cylindrical lenses)