Reflection PDF

REFLECTION What Is Reflection of Light?  When a ray of light approaches a smooth polished surface and the light ray bounces back, it is called the reflection of light. The incident light ray that land on the surface is reflected off the surface. The ray that bounces back is called the refl...

REFLECTION What Is Reflection of Light?  When a ray of light approaches a smooth polished surface and the light ray bounces back, it is called the reflection of light. The incident light ray that land on the surface is reflected off the surface. The ray that bounces back is called the reflected ray. If a perpendicular were drawn on a reflecting surface, it would be called normal. The figure below shows the reflection of an incident beam on a plane mirror. NORMAL INCIDENT RAY REFLECTED RAY i r ANGLE OF INCIDENCE ANGLE OF REFLECTION SURFACE  LAWS OF REFLECTION The laws of reflection determine the reflection of incident light rays on reflecting surfaces, like mirrors, smooth metal surfaces and clear water. The law of reflection states that The incident ray, the reflected ray and the normal all lie in the same plane The angle of incidence = Angle of reflection TYPES OF REFLECTION OF LIGHT Regular/specular reflection Diffused reflection Multiple reflection  REGULAR REFLECTION IS ALSO KNOWN AS SPECULAR REFLECTION Regular/ Specular Reflection Specular Reflection refers to a clear and sharp reflection, like the ones you get in a mirror. A mirror is made of glass coated with a uniform layer of a highly reflective material such as powder. This reflective surface reflects almost all the light incident on it uniformly. There is not much variation in the angles of reflections between various points. This means that the haziness and the blurring are almost entirely eliminated.  EXAMPLE 1. Mirror Reflection – When you look in a mirror, you see a clear and sharp image of yourself due to specular reflection. 2. Still/Calm Water Surface – A still pond or lake reflects objects like trees, buildings, or the sky, creating a mirror-like effect. 3. Polished Metal – A smooth, shiny metal surface (like stainless steel or aluminum foil) reflects light in a uniform way.  DIFFUSED REFLECTION Reflective surfaces other than mirrors, in general, have a very rough finish. This may be due to wear and tear such as scratches and dents or dirt on the surface. Sometimes even the material of which the surface is made of matters. All this leads to a loss of both the brightness and the quality of the reflection.  DIFFUSED REFLECTION In the case of such rough surfaces, the angle of reflection when compared between points is completely haphazard. For rough surfaces, the rays incident at slightly different points on the surface is reflected in completely different directions. This type of reflection is called diffused reflection and is what enables us to see non-shiny objects. DIFFUSED REFLECTION  EXAMPLE 1. Paper or Walls – Light reflects off rough surfaces like walls, books, or clothes, but the reflection is scattered in different directions, so we don’t see clear images. 2. Foggy Mirror or Steamed Glass – After a hot shower, steam makes the mirror surface rough, causing a blurry reflection. 3. Asphalt Roads – Sunlight reflects off the rough surface of roads, but the reflection is scattered, making it non-shiny.  MULTIPLE REFLECTION A single image is formed when an object is placed in front of a mirror. What happens if we use two mirrors? Since reflective surfaces such as mirrors are very good at preserving the intensity of light in a reflection, a single light source can be reflected multiple times. These multiple reflections are possible until the intensity of light becomes low to the point that we cannot see. This means that we can have almost infinite multiple reflections. We can also see an image in every individual reflection. This means that each image is the result of an image or an image of an image.  MULTIPLE REFLECTION The number of images we see depends on the angle between the two mirrors. We see tht as we go on decreasing the angle between the mirrors, the number of images increases. And when the angle becomes zero, i.e., when the mirrors become parallel, the number of images becomes infinite. This effect can be easily observed when your barber uses another smaller mirror to show you the back of your head. When this happens, not only do you see the back of your head, but you also see innumerable images of yourself. The variation of the number of images of an object placed between two mirrors with the angle between the mirrors can be described b  EXAMPLE 1. Periscope in a Submarine – Uses two mirrors to reflect light multiple times so that someone inside can see objects above the water. 2. Kaleidoscope – A toy that uses multiple mirrors at angles to create beautiful patterns with multiple reflections. TYPES OF MIRRORS Plane Mirrors Concave Mirrors Convex Mirrors  TYPES OF MIRRORS 1. Plane Mirrors: These are flat mirrors that reflect light to form an upright virtual image the same size as the object. They're commonly used in bathrooms and bedrooms. 2. Concave Mirrors: These mirrors curve inward, like the inside of a spoon. They can focus light to a single point and are used in applications like telescopes, headlights, and shaving mirrors. 3. Convex Mirrors: These mirrors curve outward and cause light to spread out. They create a smaller, wider view of an area and are often used for security and in vehicles as side mirrors. TYPES OF LENSES Convex (Converging) Lenses Concave (Diverging) Lenses Biconvex/Biconcave Lenses  TYPES OF LENSES 1. Convex (Converging) Lenses: These lenses bulge outward and converge light rays to a focal point. They're used in magnifying glasses, eyeglasses for farsightedness, and cameras. 2. Concave (Diverging) Lenses: These lenses curve inward and spread light rays apart. They're used in eyeglasses for nearsightedness and in some optical instruments. 3. Biconvex/Biconcave Lenses: Both sides of the lens are convex or concave. Biconvex lenses are used in projectors and magnifiers, while biconcave lenses are used in certain scientific instruments.  SUMMARY Angle of Incidence- The angle at which light or energy wave hits the surface of an object. Angle of Reflection- The angle at the point where an energy wave bounces back from the point of impact. Incident Ray- The wave of energy that made an impact on a surface. Reflected Ray- The energy wave that bounces back after hitting the surface of an object. Normal Line- The Line that is always PERPENDICULAR to the point of impact of a ray. Point of Incidence- The specific point at which a wave hits the surface of an object. Law of reflection- States that the angle of incidence is equivalent to the angle of reflection. Regular/Specular Reflection- The reflection of ray of light off a SMOOTH surface Diffused Reflection- Light waves bouncing off from a ROUGH surface Mixed Reflection- Images formed from a shared light wave  LETS TRY! A light ray strikes the mirror at angle of 30 degrees from the horizontal. What is the angle x where the ray leaves the second mirror?  IMAGERY CHARACTERISTICS: Image: Can be classified as Real or Virtual; this is the picture formed on a mirror. Real means rays converge, Virtual means rays diverge. Orientation: Can be Upright or Inverted, or the direction an image is presented. Upright=Right side up. Inverted=Upside down Location: Where an object will manifest in a mirror Size: The overall size of the object, Magnification means ratio of the image’s dimensions to the object’s dimensions. Larger >1, Smaller