Due to the law of reflection, the image formed by a plane mirror is the same distance behind the mirror as the object is in front of the mirror.Ĭonstruction of an image reflected in a mirror. The light does not physically come together, but rather, the eye (or camera) interprets the diverging rays as originating from an image behind the mirror. A virtual image cannot be projected on a screen. An image formed in this manner by extending back the reflected diverging rays is called a virtual image. The eye extends back the diverging reflected rays to see an image behind the mirror. The rays spread upon leaving the object, and then each ray reflects from the mirror according to the law of reflection. For simplicity, only a few of the rays are drawn. Light rays are coming from a source and reflecting off each point of the object ( AB) in all directions. By contrast, in regular reflection, the reflected light rays are orderly because each local region of the surface has a normal in the same direction.įigure 5 illustrates the formation of an image by a plane mirror. This scattering is because the local direction of the normal to the surface is different for the different rays. The reflected rays are scattered in diffuse reflection. Regular reflection is reflection from a smooth surface, such as a mirror. (b) Diffuse reflection.ĭiffuse reflection occurs when light reflects from a rough surface. Light undergoes either diffuse or regular reflection. This law applies to all reflecting surfaces. The law of reflection states that the angle of incidence equals the angle of reflection. The angle measured from the outgoing ray to the normal is called the reflected angle. The angle measured from the incoming ray to the normal is termed the incident angle. The incident ray, reflected ray, and normal all lie in the same plane perpendicular to the reflecting surface, known as the plane of incidence. The normal is a line perpendicular to the surface at the point where the incident ray reflects. The angles of the incident and reflected rays are always measured from the normal. The original ray is called the incident ray, and after reflection, it is called the reflected ray. Vision is the result of light reflected from the object.Īs shown in Figure 3, light strikes a mirror and is reflected. Through experience, the viewer has learned to extend the reflected rays entering the eye back to locate the object. The light reflects off the object and travels in straight lines to the viewer. In Figure 2, the light is coming from the sun, parallel due to the distance of the source. For an object to be visible, light from a source is reflected off the object into our eyes (except in the special case of phosphors). There are few natural sources of light, such as the sun, stars, and a flame other sources are man‐made, such as electric lights. Most visible objects are seen by reflected light. Rays from the sun are considered to be parallel when reaching the earth. Then, the light rays will be nearly parallel. Rays are perpendicular to the spherical wave fronts.įar from the source, the curvature of the wave front is small, so the wave front appears to be a plane. Depicting light as rays in ray diagrams provides a method to explain the images formed by mirrors and lenses. This straight line path shown by the arrow is called a ray. The wave fronts are spherical, and the direction of motion of the wave is perpendicular to the wave front, as depicted in Figure. A light source emits light uniformly in all directions of the three‐dimensional world. This is illustrated in Figure \( 11.34\).When an object is dropped in still water, the circular wave fronts that are produced move out from the contact point over the two‐dimensional surface. F\), which is the condition for focusing.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |