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Author Topic: Focal length  (Read 3024 times)
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on: April 01, 2012, 11:33:03 am » posted from:Adelaide,South Australia,Australia

A astronomical telescope is used to project a real image of the moon on the screen 25 cm from the eyepiece, which has a focal length of 5 cm. How far must the eyepiece be moved from its normal position. Can anyone help me how to work this one out Smiley
Fu-Kwun Hwang
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Reply #1 on: April 01, 2012, 03:53:38 pm » posted from:,,Satellite Provider

It is a telescope, so the moon can be treated as an object located at infinite.
So the image is form at the focus point.

You might be able to work out the rest! :-) Cheesy
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