What type of reflection produces an image

The mirror's smooth reflective glass surface renders a virtual image of the observer from the light that is reflected directly back into the eyes. This image is referred to as "virtual" because it does not actually exist no light is produced and appears to be behind the plane of the mirror due to an assumption that the brain naturally makes.

The way in which this occurs is easiest to visualize when looking at the reflection of an object placed on one side of the observer, so that the light from the object strikes the mirror at an angle and is reflected at an equal angle to the viewer's eyes.

As the eyes receive the reflected rays, the brain assumes that the light rays have reached the eyes in a direct straight path. Tracing the rays backward toward the mirror, the brain perceives an image that is positioned behind the mirror. An interesting feature of this reflection artifact is that the image of an object being observed appears to be the same distance behind the plane of the mirror as the actual object is in front of the mirror.

The type of reflection that is seen in a mirror depends upon the mirror's shape and, in some cases, how far away from the mirror the object being reflected is positioned. Mirrors are not always flat and can be produced in a variety of configurations that provide interesting and useful reflection characteristics. Concave mirrors , commonly found in the largest optical telescopes, are used to collect the faint light emitted from very distant stars.

The curved surface concentrates parallel rays from a great distance into a single point for enhanced intensity. This mirror design is also commonly found in shaving or cosmetic mirrors where the reflected light produces a magnified image of the face.

The inside of a shiny spoon is a common example of a concave mirror surface, and can be used to demonstrate some properties of this mirror type. If the inside of the spoon is held close to the eye, a magnified upright view of the eye will be seen in this case the eye is closer than the focal point of the mirror.

If the spoon is moved farther away, a demagnified upside-down view of the whole face will be seen. Here the image is inverted because it is formed after the reflected rays have crossed the focal point of the mirror surface. Another common mirror having a curved-surface, the convex mirror, is often used in automobile rear-view reflector applications where the outward mirror curvature produces a smaller, more panoramic view of events occurring behind the vehicle.

When parallel rays strike the surface of a convex mirror, the light waves are reflected outward so that they diverge. When the brain retraces the rays, they appear to come from behind the mirror where they would converge, producing a smaller upright image the image is upright since the virtual image is formed before the rays have crossed the focal point.

Convex mirrors are also used as wide-angle mirrors in hallways and businesses for security and safety. The most amusing applications for curved mirrors are the novelty mirrors found at state fairs, carnivals, and fun houses. These mirrors often incorporate a mixture of concave and convex surfaces, or surfaces that gently change curvature, to produce bizarre, distorted reflections when people observe themselves. Spoons can be employed to simulate convex and concave mirrors, as illustrated in Figure 4 for the reflection of a young woman standing beside a wooden fence.

When the image of the woman and fence are reflected from the outside bowl surface convex of the spoon, the image is upright, but distorted at the edges where the spoon curvature varies. In contrast, when the reverse side of the spoon the inside bowl, or concave, surface is utilized to reflect the scene, the image of the woman and fence are inverted. An object beyond the center of curvature of a concave mirror forms a real and inverted image between the focal point and the center of curvature.

This interactive tutorial explores how moving the object farther away from the center of curvature affects the size of the real image formed by the mirror. The reflection patterns obtained from both concave and convex mirrors are presented in Figure 5. The concave mirror has a reflection surface that curves inward, resembling a portion of the interior of a sphere.

When light rays that are parallel to the principal or optical axis reflect from the surface of a concave mirror in this case, light rays from the owl's feet , they converge on the focal point red dot in front of the mirror. The distance from the reflecting surface to the focal point is known as the mirror's focal length.

The size of the image depends upon the distance of the object from the mirror and its position with respect to the mirror surface. In this case, the owl is placed away from the center of curvature and the reflected image is upside down and positioned between the mirror's center of curvature and its focal point.

The convex mirror has a reflecting surface that curves outward, resembling a portion of the exterior of a sphere. Light rays parallel to the optical axis are reflected from the surface in a direction that diverges from the focal point, which is behind the mirror Figure 5. Images formed with convex mirrors are always right side up and reduced in size.

These images are also termed virtual images, because they occur where reflected rays appear to diverge from a focal point behind the mirror. The manner in which gemstones are cut is one of the more aesthetically important and pleasing applications of the principles of light reflection. Particularly in the case of diamonds, the beauty and economic value of an individual stone is largely determined by the geometric relationships of the external faces or facets of the gem.

The facets that are cut into a diamond are planned so that most of the light that falls on the front face of the stone is reflected back toward the observer Figure 6. A portion of the light is reflected directly from the outside upper facets, but some enters the diamond, and after internal reflection, is reflected back out of the stone from the inside surfaces of the lower facets.

These internal ray paths and multiple reflections are responsible for a diamond's sparkle, often referred to as its "fire".

An interesting consequence of a perfectly cut stone is that it will show a brilliant reflection when viewed from the front, but will look darker or dull from the back, as illustrated in Figure 6. Light rays are reflected from mirrors at all angles from which they arrive. In certain other situations, however, light may only be reflected from some angles and not others, leading to a phenomenon known as total internal reflection. This can be illustrated by a situation in which a diver working below the surface of perfectly calm water shines a bright flashlight directly upward at the surface.

If the light strikes the surface at right angles it continues directly out of the water as a vertical beam projected into the air. This predictability concerning the reflection of light is applicable to the reflection of light off of level horizontal surfaces, vertical surfaces, angled surfaces, and even curved surfaces. As long as the normal perpendicular line to the surface can be drawn at the point of incidence, the angle of incidence can be measured and the direction of the reflected ray can be determined.

A series of incident rays and their corresponding reflected rays are depicted in the diagram below. Each ray strikes a surface with a different orientation; yet each ray reflects in accordance with the law of reflection. In physics class, the behavior of light is often studied by observing its reflection off of plane flat mirrors.

Mirrors are typically smooth surfaces, even at the microscopic levels. As such, they offer each individual ray of light the same surface orientation. But quite obviously, mirrors are not the only types of objects which light reflects off of. Most objects which reflect light are not smooth at the microscopic level. Your clothing, the walls of most rooms, most flooring, skin, and even paper are all rough when viewed at the microscopic level.

The picture at the right depicts a highly magnified, microscopic view of the surface of a sheet of paper. Reflection off of smooth surfaces such as mirrors or a calm body of water leads to a type of reflection known as specular reflection. Reflection off of rough surfaces such as clothing, paper, and the asphalt roadway leads to a type of reflection known as diffuse reflection.

Whether the surface is microscopically rough or smooth has a tremendous impact upon the subsequent reflection of a beam of light.

The diagram below depicts two beams of light incident upon a rough and a smooth surface. A light beam can be thought of as a bundle of individual light rays which are traveling parallel to each other. Each individual light ray of the bundle follows the law of reflection.

If the bundle of light rays is incident upon a smooth surface, then the light rays reflect and remain concentrated in a bundle upon leaving the surface.

On the other hand, if the surface is microscopically rough, the light rays will reflect and diffuse in many different directions. For each type of reflection, each individual ray follows the law of reflection. However, the roughness of the material means that each individual ray meets a surface which has a different orientation. This section will cover spherical mirrors. Spherical mirrors can be either concave or convex.

The center of curvature is the point at the center of the sphere and describes how big the sphere is. These concepts are shown in. Spherical Mirrors : This figure shows the difference between a concave and convex mirror. In a concave mirror, the principal axis is a line that is perpendicular to the center of the mirror. The easiest way to visualize what a image will look like in this type of mirror is a ray diagram. Before that can be done, the focal point must first be defined. This point is half way between the mirror and the center of curvature on the principal axis.

The distance to the focal point from the mirror is called the focal length. We can see from the figure that this focal length is also equal to half of the radius of the curvature. Concave Ray Diagram : This is a ray diagram of a concave mirror. The steps taken to draw are the same as those in a plane mirror. In convex mirrors, the principal axis is the same as in a plane or concave mirror, perpendicular to the center of the mirror.

In this case, the focal point is behind the mirror. A convex mirror has a negative focal length because of this. The focal point is the same distance from the mirror as in a concave mirror. This is shown in. Convex Mirror Ray Diagram : A convex mirror with three rays drawn to locate the image. Each incident ray is reflected according to the Law of Reflection. The reflected rays diverge. If the reflected rays are extended behind the mirror, then their intersection gives the location of the image behind the mirror.