Describe a method to measure the focal length of a convex lens.

Asked by  | 23rd Apr, 2008, 08:04: PM

Expert Answer:

 This is best done using the sun as the light source (the sun is so far away, its light rays reach the earth essentially parallel.) Stand with your back to the sun. Hold the lens so the sun shines through it and onto a sheet of paper. Move the lens towards and away from the paper until the dot of light is focused. The distance from the center of the lens to the surface of the paper is the focal length.


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Answered by  | 24th Apr, 2008, 11:02: PM

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