Convex Mirrors
Convex mirrors are curved mirrors where the reflective surface bulges outwards. They diverge light rays, causing the reflected image to appear smaller and upright. These mirrors are commonly used in security mirrors, side-view mirrors in vehicles, and in certain optical devices where a wide field of view is required.
5 Key excerpts on "Convex Mirrors"
eBook - ePubJanice VanCleave's Engineering for Every Kid
Easy Activities That Make Learning Science Fun
- Janice VanCleave(Author)
- 2011(Publication Date)
- Wiley(Publisher)
...A concave lens has a surface that is curved inward like the bowl of a spoon. This lens causes light rays passing through it parallel to its principal axis to diverge, meaning that light rays bend away from the principal axis. A mirror has a surface that reflects (bounces back from a surface) light. If a mirror is flat, light will be reflected at the same angle that it hits the mirror’s surface as shown in the diagram where angle A equals angle B. The surface of a concave mirror curves inward. If the light rays hitting a concave mirror are parallel to the principal axis, they will be reflected toward the focal point. This means that these reflected rays converge at the focal point in front of the mirror. Convex Mirrors have a surface that curves outward. This surface causes light rays parallel to the principal axis to be reflected away from the principal axis—that is, to diverge. Mirrors and lenses are used in optical equipment such as microscopes and telescopes. Refracting telescopes use only lenses while reflecting telescopes use both mirrors and lenses. Lenses or a combination of lenses and mirrors help your eyes gather more light so that you see distant objects better through a telescope. Because of the way lenses or the combination of lenses and mirrors in most telescopes bend light rays, the images (representations of physical objects formed by a lens or mirror) you see are upside down. Exercises 1. Which diagram, A or B, shows light being reflected from a mirror’s surface? 2. Which diagram, A, B, or C, represents light diverging as it reflects from a convex mirror? Activity: UP OR DOWN Purpose To determine the effect of the shape of a mirror on the image it produces. Material large metal spoon Procedure 1. Hold the spoon with the inside of the bowl facing you. 2. Move the spoon back and forth from your face until the clearest image is formed. Observe whether the image is right side up or upside down. 3...
eBook - ePub- Galen C. Duree(Author)
- 2011(Publication Date)
- For Dummies(Publisher)
...The focal point is virtual because the light actually reflects and travels away from the common point (not through it). Concave lenses (lenses whose surfaces bow in toward the center of the lens) diverge incident parallel rays such that the rays seem to come from a point on the incident side of the lens, as shown in Figure 5-6. With Snell’s law, you can determine the new propagation direction. The rays appear to diverge away from the virtual focal point; you know it’s virtual because the light actually refracts (bends) and doesn’t travel through the point. Figure 5-5: Virtual focal point created by a convex mirror. Figure 5-6: Virtual focal point produced by a concave lens. Chapter 6 Imaging with Mirrors: Bouncing Many Rays Around In This Chapter Reflecting on flat, convex, and concave mirrors Examining the characteristics of mirror-produced images C hapter 4 shows you that you can change where light goes by using reflection, where light bounces off a surface. But you can further control the reflection of light with very shiny surfaces called mirrors. Mirrors are special light reflectors because they can make images of objects appear at locations other than where the actual object is located. Unlike regular objects, which reflect the incident light in all directions, mirrors reflect light but keep the relative orientation of the incoming rays. This characteristic is why you can see an image in a mirror but not in this page. In Chapter 4, I show the basic idea for all reflected light using a single ray — that the angle of incidence (the orientation of the incoming light ray) is the same size as the angle of reflection (the orientation of the outgoing, or reflected, ray). But to see the objects around you, you need more than one ray, and using the law of reflection for many rays is a tedious task, at best...
eBook - ePub- Randy O. Wayne(Author)
- 2019(Publication Date)
- Academic Press(Publisher)
...When a ray of light in this beam moves along the principal axis and strikes the mirror, it is reflected back on itself. When a ray of light in this beam strikes the mirror slightly above or below the principal axis, the ray makes a small angle with the normal and consequently the reflected ray is bent slightly toward the principal axis. If the incident ray strikes the mirror farther away from the principal axis, the reflected ray is bent toward the principal axis with a greater angle. In all cases < i =< r, and the reflected rays from every part of the mirror converge toward the principal axis at a point called the focus. The focus is exactly midway between the mirror and the center of curvature (R). The focal length of a concave mirror is equal to − R /2 and consequently it is positive. The focal length of a mirror is the distance between the focus and the vertex (Fig. 2.6). Fig. 2.6 A beam of light, propagating parallel to the principal axis of a concave mirror, is brought to a focus after it reflects off the mirror. The focal point is equal to one-half the radius of curvature. Figs. 2.7 and 2.8 show examples of image formation by spherical mirrors when the object is placed behind or in front of the focus, respectively. Fig. 2.7 A virtual erect image is formed by the eye and brain of a person looking at the reflection of an object placed between the focus and a concave mirror. The virtual image of a point appears at the location from which the rays of that point appear to have originated. Fig. 2.8 A real inverted image is produced by a concave mirror when the object is placed in front of the focal point. The farther the object is from the focal point, the smaller the image, and the closer the image is to the focal plane. Using the law of reflection, we can determine the position, orientation, and size of the image formed by a concave mirror...
eBook - ePub- Tony Farine, Mark A. Foss(Authors)
- 2013(Publication Date)
- Routledge(Publisher)
...Consequently, convex lenses may also be referred to as converging lenses. The shortest distance between the lens and the point at which light rays converge is called the focal length, and the point of convergence is the focal point or principal focus. Note that in the case of a convex lens, the focal point is behind the lens. If a piece of paper is held at this point, parallel rays of light from a distant object pass through the lens and are brought to a focus on the paper. This is a simple experiment that most children who have owned a magnifying glass have performed on a sunny day. When the magnifying glass is held facing the sun and the paper is held at the focal point, a yellow dot comes into focus on the paper. This is actually an image of the sun. Such an image is described as being real, since it can be projected on to a surface and viewed. In addition, the image in this case is also diminished (smaller than the object) and inverted (upside-down). This simple experiment is illustrated in Figure 12.9. Convex lenses are also used in the correction of certain vision defects. This is explained in Practice point 12.1. Figure 12.9 Using a convex lens to produce an image of the sun. Practice point 12.1 Convex lenses and the eye Figure 12.10 is a cross-sectional diagram of the eye. The eye is a hollow spherical structure, the outer part of which is formed from three coats. The outermost is the tough sclera; interior to this is the vascular choroid. The innermost layer is the light-sensitive retina. At the front of the eye, the sclera becomes transparent, and this is known as the cornea. A thin transparent membrane called the conjunctiva covers the cornea, and this also forms the inner surface of the eyelids. When we look at the eye from the front, we can see through the cornea to a pigmented doughnut-shaped muscle that is part of the choroid. What is this pigmented muscle called? This is the iris...
eBook - ePubThe Complete Guide to Perspective Drawing
From One-Point to Six-Point
- Craig Attebery(Author)
- 2018(Publication Date)
- Routledge(Publisher)
...Understand the relationship between the viewer, the incidence angle, and the virtual image. Knowledge is the best tool. In addition, have at hand a collection of curved reflective objects. Metallic paper can be purchased at most art stores, and bent into many different shapes. Seeing the actual reflections brings the science to life. With an understanding of the science, and a collection of reflective objects to refer to, intelligent and convincing reflection estimations can be made. Figure 31.4 It was a great deal of work to draw this single reflection. Reflecting an entire environment in a curved surface is an unreasonably difficult task. Concave Surfaces There is a subject even more difficult than convex surfaces: concave surfaces. Fortunately, reflective concave surfaces are not common; they will be briefly addressed nonetheless. To fully cover the complexity of this topic would require more space than is available, so here is an overview. Concave surfaces have a center point (the center of the reflective surface’s arc) and a focus point (a point halfway between the center point and the mirror) (Figure 31.5, upper left). While the rule governing the angle of incidence and angle of reflection to normal still applies, the angle of reflection always passes through the focus point (Figure 31.5, upper right). Four examples of reflections on concave surfaces are presented. The reflections are quite different depending on the position of the object being reflected. Sometimes the reflection is reversed; sometimes it is upright. Reflections of objects between the viewer and the center point appear smaller, reversed, and in front of the mirror (Figure 31.5). Reflections of objects between the focus point and center point appear larger, reversed, and in front of the real object (Figure 31.6, top). Objects at the focus point disappear—in theory...
