MIRRORS_LENSES_LECTURE

Quarter 2 - Module 3: Qualitative Characteristics of Images

Light Definition: Light is a natural agent that stimulates sight; it is a form of energy classified as electromagnetic radiation, which spans a wide spectrum of wavelengths.
Source of Light: Natural and artificial sources emit light. Natural sources include celestial bodies like the sun and stars, while artificial sources encompass light bulbs, LEDs, and lasers.
Photon: Light consists of tiny packets of energy known as photons, which carry electromagnetic energy and can exhibit both wave-like and particle-like properties.

Travel Method: Light travels in waves, which means it does not require a medium (like air or water) to propagate its energy, allowing it to move through the vacuum of space.
Light Rays: Light radiates from a source in straight lines called rays, forming the basis of geometric optics. The behavior of these rays is crucial in understanding image formation.

Absorption: When light encounters matter, some wavelengths are absorbed based on the material's properties, transforming into heat energy. This process is critical in applications like solar energy conversion.
Transmission: In transparent materials, light that is not absorbed passes through, allowing for phenomena such as refraction, which alters the light's path.
Reflection and Scattering:
- Reflection: This occurs on smooth surfaces like mirrors, enabling clear image formation due to the consistent angle of reflection.
- Scattering: On rough surfaces, light scatters in various directions, which is responsible for the diffuse appearance we see in materials such as frosted glass or clouds.

Definition: Reflection is the bouncing of light rays off an object, which allows us to see our surroundings.
Laws of Reflection:
1. The incident ray, reflected ray, and the normal line to the reflecting surface all lie in the same plane.
2. The angle of incidence (the angle between the incident ray and the normal) equals the angle of reflection (the angle between the reflected ray and the normal).

Image Properties:
- Virtual: The images formed in plane mirrors are virtual, meaning they cannot be projected onto a surface.
- Size: These images are the same size as the object being reflected.
- Orientation: The images maintain the same orientation as the actual object.
- Distance: The image appears to be the same distance from the mirror as the object itself.
Types of Reflection:
- Specular/Regular Reflection: This occurs when light reflects off a smooth surface, resulting in clear images.
- Diffused/Irregular Reflection: This happens when light reflects off rough surfaces, scattering the light and creating a more blurred image.

Real Image:
- Formation: Formed by real light rays converging at a focal point after reflection or refraction.
- Projection: They can be projected onto a screen and are always inverted relative to the object.
Virtual Image:
- Characteristics: Cannot be projected as they appear to exist behind the reflective surface, though they appear to the eye as if they are present.

Spherical Mirrors:
- Concave Mirror: Reflects light inward to a focal point, often used in applications such as shaving mirrors and satellite dishes; known as a converging mirror.
- Convex Mirror: The reflective surface bulges outward away from the light source, diverging light rays and providing a wider field of view; used for safety in vehicle mirrors.

Real Image Formation: Occurs when light rays converge after reflection; these images can be projected on a surface.
Image Location: Can be determined through ray diagrams involving key elements:
- Center of Curvature (C): The center of the sphere from which the mirror is part.
- Focal Point (F): The point where parallel rays converge after reflection.
- Vertex (V): The point on the mirror's surface directly facing the incoming light.
- Principal Axis: The line that passes through the center of curvature and the vertex.
- Focal Length (f): The distance from the focal point to the mirror surface, crucial in lens design.
- Radius of Curvature (R): The radius of the sphere of which the mirror is a segment.

Convex Lens:
- Description: Thicker at the center and thinner at the edges; converges incoming light rays to form real images on the opposite side when the object is outside the focal length, and virtual images when within.
Concave Lens:
- Description: Thicker at the edges and thinner at the center; diverges light rays and always forms erect, reduced virtual images regardless of the object position.

Near-Sightedness (Myopia): Condition where the eyeball is too long, causing images to focus in front of the retina; corrected using concave lenses that diverge light rays before reaching the eye.
Far-Sightedness (Hyperopia): Condition where the eyeball is too short, leading images to focus behind the retina; corrected with convex lenses that converge light rays to assist in proper image focus.

Pinhole Camera: Utilizes a tiny aperture to allow light from a specific direction to reach the film plane, demonstrating basic principles of camera operation and image formation based on light direction.
Lens Camera: Employs complex lenses to gather more light than a pinhole, resulting in clearer and more detailed images. This design allows for various aperture settings and zoom capabilities that enhance photographic versatility.