Conceptual ideas develop logically and sequentially, ultimately leading into the mathematics of the topics. Alevel physics advancing physicsrefraction wikibooks, open. State snells law of refraction and show with appropriate drawings how it applies to light rays at. Snells law a monochromatic light ray passes from air n 1. Each lesson includes informative graphics, occasional animations and videos, and check your understanding sections that allow the user to practice what is. Furthermore, is the angle of the incident light ray from air with respect to the normal, while is the angle of the refracted ray in.
An alternative discussion of snells law could be to discuss. If we label the angle of incidence as i and the angle of refraction as r, then it can be shown that when travelling from a vacuum into a material, the ratio remains constant for all values of i. Alevel physics revision edexcel physics alevel revision notes. Thus to find the refractive index of our new plastic, we need to divide the speed of light in a vacuum c, by the speed that light travels in the medium v. Lets make a ratio of the two refractive indices the two n values for the air and water. Geometrical light rays fermats principle of least time fermats principle applied to reflection and refraction snells law examples imaging and the lens law the lens makers formula thin lens and keys for ray tracing optical. Snells law, in optics, a relationship between the path taken by a ray of light in crossing the boundary or surface of separation between two contacting substances and the refractive index of each. See more ideas about physics, a level physics and chemistry. The study of physics enables learners to be creative and innovative in industry and society can. I got an a in physics gcse so here are my notes physics igcse revision notes made for edexcel but can be used for other boards. One important consequence of snells law of refraction is the phenomenon of.
This law was discovered in 1621 by the dutch astronomer and mathematician willebrord snell also called snellius. At a certain angle of incidence called the critical angle, the light. History of snell s law snell s law describing refraction was first recorded by ptolemy in 140 a. Refractive index snells law group experiment lesson 5 3. Light rays travel in different mediums at different speeds. Refraction, geometrical optics from alevel physics tutor. An objects index of refraction is described using snells law, which relates the speed of light in a material to the speed of light in a vacuum.
But can we predict how far waves will change direction. Does anyone know any links websites to notes for the aqa physics alevel course the course that started in september 2016. This section considers electromagnetic waves from radio through to gamma. If you have other applications, or relevant sources, please do bring them up. Snells law also known as snelldescartes law and the law of refraction is a formula used to describe the relationship between the angles of incidence and refraction, when referring to light or other waves passing through a boundary between two different isotropic media, such as water, glass, or air in optics, the law is used in ray tracing to compute the angles of incidence or. Where and represent the index of refraction for air and water, respectively. The best physics o level notes compiled from all around the world at one place for your ease so you can prepare for your tests and examinations with the satisfaction that you have the best resources available to you.
Physics notes form 3 free download kcse revision notes pdf. The light is bending away from the normal as it enters a rarer material. Physics notes physics notes form 3 physics notes form 3 klb physics notes form 3 pdf physics notes form 4 physics notes form 4 chapter 2 physics notes form 4 klb physics notes form 4 pdf physics notes form 4 pdf physics notes form four physics notes form four klb. Light rays represent the direction of travel of the waterfronts. The refractive index can be calculated from the sin of the angles of the light measured in the materials.
The physics classroom tutorial presents physics concepts and principles in an easytounderstand language. Snells law and the refractive index so we know that waves slow down when they enter optically denser materials, and bend towards the normal line. As with any equation in physics, the snells law equation is valued for its predictive ability. Powerpoint revises refraction and the direction of bending, then introduces snells law.
Coherence, path difference and phase difference are really important. Application of these principles through the use of a polarizing microscope allows geologists to confirm the hand specimen identification of minerals, to. D first described by relationship by snellius in 1621 first explained in 1650 by fermats principle of least time. An example to understand this better is that of placing a strawstick in a glass of water wherein it to be bent when viewed from any other angle than 90 0 to the surface.
Snells law and the index of refraction introduction. Sound diffracts so much that snells law is seldom a useful approximation to sound wave behavior. O level physics syllabus is designed to inclusively cater for all categories of learners. For the best revision experience, use both the notes and the videos at the same time to help you follow along. The physics classroom grants teachers and other users the right to print this pdf document and to download this pdf document for private use. Refraction of light rays, examples and solutions physics.
The pdf version of the teacher toolkit on the topic of refraction and snells law is displayed below. If we label the angle of incidence as i and the angle of refraction as r, then it can be shown that when travelling from a vacuum into a material, the ratio remains constant for all. An optical fibre is a thin, transparent fibre, usually made of glass or plastic, for transmitting light. Using snells law to predict an angle value as with any equation in physics, the snells law equation is valued for its predictive ability.
Wave theory of light is used to explain the reflection and refraction of light. The change in direction or bending of a light wave passing from one transparent medium to another. Using snells law, determine the constant when the angle of incidence and the angle of refraction are. One of the most important parameters that measures optical properties of a medium is the index of refraction. Snells law relates the angle of incidence and the angle of refraction to the refractive index of a medium by sin where i is the angle of incidence and r is the angle of refraction. Snells law this equation shows the inverse relationship between the angles and indices. Electromagnetic waves, snell s law we now embark on a fourweek digression to consider the physics of the interaction of light with nonopaque minerals. Snells law relates the angle of incidence to the angle of refraction.
It is shown that the sizes of the angles of incidence and refraction are related to the speed of the light through the medium. In your igcse examination you might be asked to describe an experiment to investigate snells law or determine the refractive index of a. Total internal reflection is a very useful natural phenomenon since it can be used to confine light. All physics formulas pdf formula of mean median and mode. Waves can pass through other waves, like ripples on a pond, with their combined amplitude the sum of the individual dispacements at any one time the principle of superposition. Snells law applies to the refraction of light in any situation, regardless of what the two media are. I have some notes written for the old spec on my blog here on tsr called kyxs university experience.
Total internal reflection in glass depends on the fact that its critical angle. If light is propagating from a more dense to a less dense medium in the optical sense, i. Transverse and longitudinal waves, oscillating systems, phase difference, the wave equation, the electromagnetic spectrum and its uses and dangers, reflection and refraction, refractive index, snells law, measuring refractive index, critical angles, total internal reflection, polarisation, using polarised light, pulseecho techniques, ultrasound. Refraction a2levellevelrevision, physics, particles. The bending of a light ray as it passes from air to water is determined by snells law. Snell s law was used to calculate the angle of refraction. By using these notes, you are accepting the standard terms and conditions of scool, as stated in the scool website uk. Snell s law, in optics, a relationship between the path taken by a ray of light in crossing the boundary or surface of separation between two contacting substances and the refractive index of each. One important consequence of snells law of refraction is the phenomenon of total internal re. Pdf ordinary level physics lecturers notes 1 st edition peter. Alevel physics revision notes 2015 scool the revision. From snells law, the angle of refraction can be calculated if the refractive index of the two materials is known. The best physics o level notes o and a level notes. Refraction calculations and total internal reflection s.
The best physics as and a level notes, revision guides, tips and websites compiled from all around the world at one place for your ease so you can prepare for your tests and examinations with the satisfaction that you have the best resources available to you. Notice that this time, the angle of refraction is larger than the angle of incidence. Ordinary level physics lecturers notes 1st edition s3 by peter abraham in. We can derive it by considering a spherical wave emanating from the center of the sphere with the same radius r 1. Refraction revision and snells law introduction lesson. The ratio constant is called the relative refractive index n. If any three of the four variables in the equation are known, the fourth variable can be predicted if appropriate problemsolving skills are employed. Image formation due to refraction application of refraction 3. See more ideas about physics, physics notes and physical science. Went through ppt with students to the direction of bending. For manual work, the doflimits are usually indicated on the. Below you will find our collection of revision notes and video tutorials.
A whole lesson, lesson plan included, on refraction and snells law. Snell s law and the refractive index so we know that waves slow down when they enter optically denser materials, and bend towards the normal line. The frequency f of such strip oscillations can be empirically related to the length l. This important law, named after dutch mathematician willebrord snell. From work on relative refractive index, back to top. Physics is the scientific study of matter and energy and how they interact with each other. Snells law has a wide range of applications in physics especially in the.
Solving more numerical will help the student in understanding snells law. In figure 314a, point object s sends nonparallel rays toward a plane mirror, which reflects them as. Snells law is a relationship between the angles of incidence and refraction and the. When the effect of lenses or mirrors on paths, we consider the drawing of diagrams using light rays and normals. One of the most common applications of total internal reflection is in fibre optics. The physics classroom teacher toolkits snells law snells law pdf version. To answer this question, well need to make use of snells law. Electromagnetic waves in vacuum always propagate with speed c 3.957 894 705 739 625 1343 725 674 1162 325 1511 773 248 1620 221 1190 1382 291 1448 370 1482 610 915 171 379 191 1371 598