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 Apr 13th 2010, 05:35 PM #1 Junior Member   Join Date: Apr 2010 Posts: 1 Light and lenses In a convex lens if a object is 3 focal lengths away, it is possible to have a magnification of above 1?
Apr 13th 2010, 09:19 PM   #2
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Location: Udupi, Karnataka, India
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 Originally Posted by sinjid9 In a convex lens if a object is 3 focal lengths away, it is possible to have a magnification of above 1?
Hi sinjid9, welcome to PHF.
The answer to your question is "NO".
When the object is on 2f, the image is also on 2f and the magnification is 1. If the object is beyond 2f, the image is between f and 2f. So the image distance is smaller than the object distance. Hence the magnification is less than one.

Last edited by sa-ri-ga-ma; May 13th 2010 at 04:58 AM.

 May 13th 2010, 02:23 AM #3 Banned   Join Date: May 2010 Posts: 6 When nothing gets in its way, light travels in a nice straight line. But when you put a chunk of clear glass or plastic in the way, light may not keep traveling straight. If light encounters a piece of glass or plastic at an angle, the light bends. The bigger the angle, the more the light bends. The light may bend again when it moves from inside the glass or plastic into the air. If the light meets the air at an angle, the light bends. The bigger the angle, the bigger the bend. The beams of light shine through the clear plastic of the lens and encounter the curved surface where the plastic of the lens meets the air. Beams of light that meet this surface straight on keep on going straight. But some beams of light meet the curved surface at an angle. Those beams bend. This lens is curved on one side and flat on the other. The lens in your eye is curved on both sides, but it works in the same way.

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