Science 8 Chapter : Reflecting Light off Surfaces

Specular Reflection The reflection of light off a smooth, shiny surface

Laws of Reflection The incident ray, the reflected ray, and the normal all lie in the same plane. normalplane The angle of incidence equals the angle of reflection.angle of incidenceangle of reflection

Diffuse Reflection Occurs when light hits an irregular surface

11.3 Describing images

Optical Device Produces an image OF an object

There are two types of images created from an optical device Virtual and Real images

Virtual image: an image in which the outgoing rays from a point on the object always diverge (spread apart).rays It will appear to converge in or behind the optical device (i.e., a mirror). A simple example is a flat/plane mirror where the image of oneself is perceived at twice the distance from oneself to the mirror.flat/plane mirror That is, if one is half a meter in front of the mirror, one's image will appear to be at a distance of 1 meter away (or half a meter inside or behind the mirror). Because the rays never really converge, one cannot project a virtual image onto a screen.

Real Image: a representation of an object (source) in which the perceived location is actually a point of convergence (come together at a point) of the rays of light that make up the image.rays of light If a screen is placed in the plane of a real image the image will generally become visible on the opaque screen. Examples of real images include: – the image seen on a cinema screen (the source being the projector),cinema screen – the image produced on a detector in the rear of a camera,detector in the rear of a camera – and the image produced on an eyeball retina (the camera and eye focus light through an internal convex lens).retina A real image occurs where rays converge, whereas a virtual image occurs where rays only appear to converge.

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Characteristics of images 1.Size (ex) image is smaller than original object) 2.Attitude (upright or inverted) 3.Location of image (ex.) behind the mirror 4.Type (virtual or real)