Light from this page or screen is formed into an image by the lens of your eye, much as the lens of the camera that made this photograph. Consider a sound wave since it is easier to visualize. A lens is a transparent substance of glass or plastic, bound by two surfaces, whose at least one surface is curved. Three phenomena reflection, refraction, and diffraction help you predict where a ray or rays of light will go.
This type of mirror will produce only smaller and virtual images. In this case, the lens has been shaped so that all light rays entering it parallel to its axis appear to originate from the same point, f, defined to be the focal point of a diverging lens. That means we have been playing with lenses for a long time. Although in this video we are only going to talk about mirrors. Mirrors and lenses both have the ability to reflect or refract light. A converging lens always has two focal points, the primary focal point on the near side of the lens towards the oncoming light rays and a secondary focal point on the far side of the lens away from the oncoming light rays. Geometrical optics will help you understand the basics of light reflection and refraction and the use of simple optical elements such as mirrors, prisms, lenses, and fibers. So lets see how it goes, suppose that ive got an object out here in air and then ive got a piece of glass thats curved outward like this in a convex way.
Ray hits the vertex of mirror 1 and reflects with same angle. Ancient egyptians, babylonians, and greeks, all had a sense of basic optics. Not only that, but we will even backtrack a little and start with a discussion of basic ideas about light and vision that predated the discovery of electromagnetic waves. Spherical mirror is a curved mirror which is a part of a hollow sphere. Positive and negative lenses can both form real and virtual images. Rays of light parallel to the principal axis after reflection from a concave mirror meet at a point converge. Convex converging lenses can form either real or virtual images cases 1 and 2, respectively, whereas concave diverging lenses can form only virtual images always case 3. This book provides an introduction to the eld of optics from a physics perspective. The focus of convex lenses is where rays parallel to principal axis go.
It seems that no two professors or teachers or books. A ray passing through the center of any lens continues in a straight line. Concaveconvex mirror and lenses for ssc cgl, chsl, mts, nda, cds railway exams. With a converging lens, paraxial rays that are parallel to the principal axis converge to the focal point, f. Use the lensmakers equation to determine the focal length of a thin lens. Physics to find out more about mirrors and lenses, visit the glencoe science. The viewing screen should cover only half of the hole in the component holder so that light from the filament reaches the mirror. The light rays leave the mirror or lens on the out side. The effects of lenses and mirrors on a ray can be determined using fermats principle, through trigonometry and the application of snells law, to trace the path of a light ray from a point on the source to the image point. A more specialized form of lenses, spectacles appeared around the 12 th century, but it took until contemporaries of galileo and later newton to develop a decent telescope we should all like lenses. Since lenses pass light through them unlike mirrors it is useful to draw a focal point on each side of the lens for ray tracing. If a lens is used to form an image of something infinitely far away, the distance from the lens to. Should that not be a minus sign on the left hand side. If the object and image are the same distance from the mirror and magnification is 1, then as the object approaches the mirror at a certain speed, the image is approaching the plane mirror at the same speed, therefore you approach the image more quickly than you approach.
It is shown in most basic books on optics see references listed at end of this module that image. According to georgia state university, virtual images are formed at the location where the paths of the primary light rays intersect when projected backward from their direction beyond a lens. A spherical mirror consists of a small section of the surface of a sphere with one side of the surface covered with a polished reflecting material, usually silver or aluminum. We will talk about how these things work using the following. Light rays follow a complex route as they encounter mirrors or pass through a. The first lens in a refracting telescope that light from a celestial object passes though. For a mirror or lens, the light rays come into the optical device from one side. It focuses primarily on the wave and ray descriptions of light, but also includes a brief introduction to the quantum description of light. The focal length, f, is the distance between f and the lens. As of 2010, mirrors and lenses are so prevalent that most people use them every day, regardless of whether or not they consciously perceive the use. In this section, we will use the law of refraction to explore the properties of lenses and how they form images.
Here are some useful rays in determining the nature of the images formed by converging and diverging lens. Or should it be a plus sign for mirrors and minus for lenses. Kids learn about lenses and light in the science of physics including concave, convex, converging, diverging, focal point, meniscus, and plano lenses. As all who have ever tried lens and mirror calculations know, the biggest difficulty we have to face is that of the dreaded sign conventions. The focal lengths of a biconvex lens and a concave mirror are shown in figures 1 and 2, respectively. This book is an algebra based treatment of electric force, electrical energy, circuits, magnetism, faradays law, light and optics, introduction to modern physics, atomic physics and nuclear physics. Lenses are found in a huge array of optical instruments, ranging from a simple magnifying glass to the eye to a cameras zoom lens. A system of lenses andor mirrors forms an image by gathering rays from an object and then causes them to converge or diverge.
The concave lens is a diverging lens, because it causes the light rays to bend away diverge from its axis. Physics mirrors are where light can be reflected and reconvened to form images. Download geometric optics download free online book chm pdf. Book 5 in the light and matter series of introductory physics textbooks. Mirrors, which have curved surfaces designed to reflect rays, also form images. While a ray diagram may help one determine the approximate location and size of the image, it will not provide numerical information about image distance and object size. You will also verify the mirror and lens equation and the magnification formula by direct measurement of the positions of object and image. A mirror is a glass surface with a silvery backing, that produces an image through reflection. Telescopes, microscopes, cameras, projectors, your eyes, all have one thing in common. Rotating mirror sweeps the scene until the image is aligned with fixed image from mirror m pretty much stereovision and window correlation. Download physics of light and optics download free online book chm pdf.
The mirror equation expresses the quantitative relationship between the object distance do, the image. You can skip questions if you would like and come back. This property has put mirrors and lenses in use for centuries. Ifthe outside, or convex surface, is silvered, we have a convex mirror. In this section, we use the snells law to explore the properties of lenses and how they form images. This collection of interactive simulations allow learners of physics to explore core physics concepts by altering variables and observing the results. You will recognize the causes of aberrations in lenses and mirrors and how these can be. Reflection and refraction, lens and mirror calculations, optical instruments and optical aberrations. If you are watching this video while studying about lenses. We all know that the importance of mirrors, lens etc. Exploring images with thin lenses and mirrors 1 of 20.
As all who have ever tried lens and mirror calculations know, the biggest difficulty. By taking readings of image and object distances for different positions, a graph can be drawn. The viewers eye is from the objective lens, and they desire a magnification of. Physics 106 lab lenses and mirrors physics dept home. Images in concave mirrors appear upside down, real and reduced. The goal of the experiment is to be able to analyze ray diagrams so as to determine fundamental properties of image formation. It bends light further away in the middle, more like the. When light falls on a highly polished surface like a mirror. When an object is placed in front of a plane mirror the image is. This section contains more than 70 simulations and the numbers continue to grow. Concave mirrors curve inward, creating a focal point in front of the mirror. Optics exam2 and problem solutions physics tutorials. Light waves can be bent and reflected to form new and sometimes altered images.
Two prisms can bend light toward the principal axis acting like a crude converging lens but. Choose your answers to the questions and click next to see the next set of questions. Alevel physics, section thermal physics, 6 chapters, 34 pages, 1. Lenses concave and convex apparatus selection of lenses, collimated light source, e. Light and optics truefalse decide whether each of the following statements is true or false. Figure 3 illustrates how images are formed by a plane mirror and curved mirrors. And the name of this book is optics and modern physics by dc pandey.
The refraction at the first surface is balanced by the refraction at the second surface. The focal length f of a lens can be found quite accurately by moving an illuminated object infront of a lens so that an image is cast on a screen. It curves light away from its middle, like the outside portion of a bowl. Jan 26, 2018 this is a highly reputed and good quality content book. Introduction to geometric optics for lenses and mirrors. In this book you will find a lot of questions, solved examples and short, very short, one wors questions related to particular topic.
Summary of mirrors and lenses department of physics. Ray, coming from first mirror turns back with same path after reflecting from second mirror. Mirrors and lenses in this experiment you will learn to determine the focal lengths of mirrors and lenses. Understanding how light rays can be manipulated allows us to create better contact lenses, fiber optic cables, and high powered telescopes. The rays of light coming from the point reflect according to. A lens is a transparent device with two curved surfaces, usually made of glass or plastic, that uses refraction to form an image of an object. Lenses and mirrors static web pages for physics and. The same sort of rules apply, just with a few modifications. Lenses in optics applications types of lenses physics. Object image and focal distance relationship proof of formula object image height and distance relationship.
The light will then be inverted at the focal plane. Also, lenses have two focal points, one on each side of the lens. A upright, magnified and real b upright, the same size and virtual c inverted, demagnified and real d inverted, magnified and virtual. An image is formed when the light rays coming from an object meet at a point after reflection from a mirror or refraction from lens. Two concave mirrors are placed on same principal axis. For the rays shown in figures 12, light is assumed to be coming from the left, and going toward the right. A compound microscope has two convex lenses, separated by 10.
Shown is a hemispherical view of a sound wave emitted by a pulsating sphere. Uses of convex lens,concave lens,convex mirrors,concave. Table 1 summarizes the three types of images formed by single thin lenses. Homework resources in mirrors and lenses physics science.
As of 2010, mirrors and lenses are so prevalent that most people use them every day, regardless of whether or not they consciously. They should try to describe any images they form in terms of magnification, upright or inverted, real or virtual. There are standard and innovative uses for mirrors. It is proven in introductory physics textbooks1 that the image and. A more specialized form of lenses, spectacles appeared around the 12 th century, but it took until contemporaries of galileo and later newton to develop a decent telescope. Light parallel to the principal axis a converges toward f after reflection from a concave mirror, and b diverges from f after reflection from a convex mirror. Exploring images with thin lenses and mirrors 1 of 20 introduction. Because mirrors do not usually absorb much light, most of the light is redirected upon contact with the mirror and the objects overall quality is usually preserved in the new image. Concave lenses video geometric optics khan academy. Plane silver mirrors a mirror is a device that contains a surface used to reflect light. Depictions of lenses forming real and virtual images.
Lenses and mirrors applications study for exams optics, physics uses of convex lens,concave lens,convex mirrors,concave mirrors psc online book. Real image is formed when the light reconvenes and always inverted i. Lenses remembering the basics of mirrors puts you half ways towards fully understanding lenses as well. Determination of focal length of a converging lens and mirror. Physical optics will help you understand the phenomena of light wave interference, diffraction, and polarization. Mirrors and lenses in a microscope has a tube length and objective lens with a focal length of.
Pdf optical images due to lenses and mirrors researchgate. We will instead spend most of this book making use of a simpler model of light, the ray model, which does a fine job in most practical situations. One characteristic feature of all thin lenses and concave mirrors is the focal length, f, and is defined as the image distance of an object that is positioned infinitely far way. Convex lenses, geometrical optics from alevel physics tutor. Two different types of mirror are concave and convex mirror with different properties. Keep in mind that for an object to be considered a lens it must be made of a transparent material that has an index of refraction higher than air. Mastering numericals and objectives of physics for class x. Mirrors, like lenses, can also form images that in turn are captured by your eye. Apr 10, 2020 lenses are found in a huge array of optical instruments, ranging from a simple magnifying glass to a cameras zoom lens to the eye itself. Physics lenses are curved glasses or transparent materials. A lens refracts light and creates an image that is either virtual or real. Lenses lenses refract light in such a way that an image of the light source is formed. Geometric optics converging lenses and mirrors physics lab iv objective in this set of lab exercises, the basic properties geometric optics concerning converging lenses and mirrors will be explored. In this experiment you will find images created by lenses and mirrors and study the laws that describe them.
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