268CHAPTER 23 Answers to Even Numbered Conceptual Questions 2.If the finger and the image are at the same distance from you, then they will coincide regardless of what angle you view them from. However, if one is closer than the other, they will appear to coincide only when viewed along the line connecting their positions. When viewed at any angle to this line, the finger and image are seen separately. 4.Chromatic aberration is produced when light passes througha material, as it does when passing through the glass of a lens. A mirror, silvered on its front surface never has light passing through it, so this aberration cannot occur. This is only one of many reasons why large telescopes use mirrors rather than lenses for their primary optical elements. 6.Make the mirror an efficient reflector (shiny); use a parabolic shaped mirror so that it reflects all rays to the image point, even those far from the axis; most important, use a large-diameter mirror in order to collect more solar power.
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