draw a ray diagram for the formation of an image by a concave mirror when the object is placed near to the mirror. Explain the properties of image formed in this case.
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The theme of this unit has been that we see an object because light from the object travels to our eyes as we sight along a line at the object. Similarly, we see an image of an object because light from the object reflects off a mirror and travel to our eyes as we sight at the image location of the object. From these two basic premises, we have defined the image location as the location in space where light appears to diverge from. Ray diagrams have been a valuable tool for determining the path taken by light from the object to the mirror to our eyes. In this section of Lesson 3, we will investigate the method for drawing ray diagrams for objects placed at various locations in front of a concave mirror.
To draw these diagrams, we will have to recall the two rules of reflection for concave mirrors:
Any incident ray traveling parallel to the principal axis on the way to the mirror will pass through the focal point upon reflection.
Any incident ray passing through the focal point on the way to the mirror will travel parallel to the principal axis upon reflection.
Earlier in this lesson, the following diagram was shown to illustrate the path of light from an object to mirror to an eye.
