Physics Help Forum Converging Lens Related Question

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 Jul 20th 2010, 06:15 PM #1 Junior Member   Join Date: May 2010 Posts: 6 Converging Lens Related Question An object is located 30 cm to the left of a converging lens whose focal length is 50 cm. (a) Draw a ray diagram to scale and from it determine the image distance and the magnification. (b) Use the thin lens and magnification equations to verify your answer to part (a). I can't really draw it.. here's my attempt. (Rough sketch) How do I determine the image distance?
 Jul 20th 2010, 08:41 PM #2 Senior Member   Join Date: Dec 2008 Location: Udupi, Karnataka, India Posts: 292 After refraction from the lens, two rays are diverging. Find the point from which the two rays are diverging by tracing the rays towards left. That point is the position of the image.
Jul 21st 2010, 12:51 PM   #3
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 Originally Posted by sa-ri-ga-ma After refraction from the lens, two rays are diverging. Find the point from which the two rays are diverging by tracing the rays towards left. That point is the position of the image.
Not sure what you mean by tracing the rays left.

Jul 21st 2010, 07:15 PM   #4
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 Originally Posted by Kookehs Not sure what you mean by tracing the rays left.
From a point source you can have two diverging rays.

Two diverging rays are coming out of the lens after refraction. Find the point from which they appear to be coming from. Produce these two rays in the reverse direction to find that point.

Oct 12th 2010, 06:02 PM   #5
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 Originally Posted by sa-ri-ga-ma From a point source you can have two diverging rays. Two diverging rays are coming out of the lens after refraction. Find the point from which they appear to be coming from. Produce these two rays in the reverse direction to find that point.
I suggest to use a graph paper and use a proper scale to draw the rays where they meet.

 Oct 13th 2010, 07:30 AM #6 Physics Team     Join Date: Jun 2010 Location: Mauritius Posts: 609 What sa-ri-ga-ma is telling you is to extend the lines backwards like this: Where they meet, you drop a vertical line to the focal axis and draw the image. __________________ Jerry (Got my results!) It is easier to protect your feet with slippers than to cover the earth with carpet. No one can go back and change a bad beginning; but anyone can start now and create a successful ending. If a problem can be solved, no need to worry about it. If it cannot be solved what is the use of worrying?

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