Law of Reflection of Light Class 12

The process by which light rays fall to the surface and are reflected is called light reflection. The angle of reflection at which a reflected beam hits an object, according to the law of light. When a beam hits an object and bounces in the opposite direction, the angle of reflection is formed. The reflected beam is the only one that produces the angle of reflection. Only one angle of reflection may exist for a single reflected light beam. When light rays are reflected off a surface, move from one transparent medium to another, or pass through a medium whose composition is constantly changing, they change direction. The angle of the reflected beam is equal to the angle of the incident beam when reflected on a smooth surface, according to the law of reflection. (All angles are measured in geometric optics with respect to the perpendicular to the surface, that is, a line perpendicular to the surface.) The reflected beam always falls into the plane normally defined by the incident beam and the surface. To understand the images produced by flat and curved mirrors, the law of reflection can be applied. Since most natural surfaces are rough, unlike mirrors at the scale of light wavelengths, parallel incident light rays are reflected in different directions or diffusely. The ability to see most illuminated surfaces from any position is due to diffuse reflection – the rays reach the eyes after being reflected on each part of the surface. When light flowing through a transparent medium is transferred to a boundary with another transparent medium (e.g. air and glass), some of the light is reflected and some is transferred to the second medium.

When the transmitted light enters the second medium, its direction of movement changes; It is broken. It is common to observe this law in a physics laboratory, as described in the previous part of lesson 1. To display the image of a pencil in a mirror, you need to look along a line at the location of the image. When you look at the image, the light moves towards your eye along the path shown in the diagram below. The diagram shows that the light is reflected from the mirror in such a way that the angle of incidence is equal to the angle of reflection. It`s just that the light that travels along the line of sight to your eye follows the law of reflection. (The reason for this will be explained later in lesson 2.) If you were to see along a line in a place other than the location of the image, it would be impossible for a beam of light to come from the object, be reflected by the mirror according to the law of reflection, and then move towards your eye. It is only when you look at the image that the light from the object reflects according to the mirror`s law of reflection and moves towards your eye. This truth is illustrated in the diagram below. The angle of incidence and the angle of reflection are calculated by drawing a normal line perpendicular to the reflecting surface. 3. You may have observed the image of the sun in the windows of distant buildings near the time the sun rises or sets.

However, the image of the sun is not visible in the windows of distant buildings at noon. Use the diagram below to explain and draw the corresponding light rays on the diagram. Q1: A beam of light falls at an angle of 30° with the mirror surface on a flat mirror. What will be the angle of reflection? The angle created by the reflected beam and the normal is called the reflection angle. (These two angles are designated by the Greek letter „theta,” followed by an index character read as „theta-i” for the angle of incidence and „theta-r” for the angle of reflection.) According to the law of reflection, the angle of incidence is equal to the angle of reflection when a beam of light is reflected on a surface. 1. Look at the diagram on the right. Which of the angles (A, B, C or D) is the angle of incidence? ______ What is the angle of reflection? ______ The incident radius, the reflected beam and the perpendicular to the surface of the mirror are all in the same plane, according to the first law of reflection. The principle when the light rays fall on the smooth surface, the angle of reflection is equal to the angle of incidence, so the incident beam, the reflected beam and the perpendicular to the surface are all in the same plane. A laser beam is allowed to hit the plane mirror and is reflected to demonstrate the laws of reflection. Mark the path of light and the base of the mirror with a pencil.

Measure the angle of incidence and the angle of reflection with a protractor, and we will find that: angle of incidence = angle of reflection We know that light is the form of energy that can be subjected to various phenomena such as refraction, reflection, diffraction and interference. In this session, let`s learn more about the laws of reflection (first set of thinking and second reflection theorem), types of reflection, examples, differences, and total inner thinking. Unlike mirrors, most natural surfaces are rough on the wavelength scale of light, and as a result, parallel incident light rays are reflected irregularly or diffused in many different directions. Therefore, diffuse reflection helps to see objects and is responsible for the ability to see most illuminated surfaces from any position. The phenomenon of total internal reflection is used by the fibers in the lumen of the pipeline in a curved path. Light directed at a narrow glass or plastic fiberglass is repeatedly reflected from the fiber-air interface at an angle greater than the critical angle. Optical fibers can transmit light over long distances without loss of intensity. The three laws of reflection are1. The angle between the incident beam and the normal is equal to the angle between the reflected beam and the normal2. The incident beam, the normal beam and the reflected beam are all in the same plane3. The incident beam and the refracted beam are located on either side of the normal We first complete the given diagram with the angles of incidence and reflection indicated above, and also label the incident and reflected rays.

Choose the right answer: what is the case with reflection if the second medium is a perfect dielectric? The images produced by flat mirrors and curved mirrors can be understood by the law of reflection. Q2: A light beam hits a reflective flat surface at an angle of 54° with the surface. In the diagram, the beam of light approaching the mirror is called the incident beam (denoted I in the diagram). The beam of light that leaves the mirror is called the reflected beam (denoted R in the diagram). At the point of incidence where the beam hits the mirror, a line can be drawn perpendicular to the surface of the mirror. This line is called the normal line (denoted N in the diagram). The normal line divides the angle between the incident beam and the reflected beam into two equal angles. The angle between the incident beam and the normal is called the angle of incidence. The angle between the reflected beam and the normal is called the reflection angle. (Both angles are labeled with the Greek letter „theta,” accompanied by an index character; read „theta-i” for the angle of incidence and „theta-r” for the angle of reflection.) The law of reflection states that when a beam of light is reflected on a surface, the angle of incidence is equal to the angle of reflection. When light changes from a denser medium to a lighter medium at an angle greater than the critical angle required for refraction, the light is reflected back into the denser medium. This is a phenomenon called total inner reflection.

Light subjected to total internal reflection also follows the ordinary laws of reflection for light, as shown below: with curved mirrors with a smooth surface, we can see the reflection images virtually or actually. That is, the images produced by curved mirrors can be real (collected and seen on a screen) or virtual (not collected on a screen, but only seen).