Q31 of 60 Page 1

A student has obtained a point image of a distant object using the given convex lens.

To find the focal length of the lens he should measure the distance between the:

Because the object is very far its distance is taken to be infinity, u = ∞


Thus, 1/u=0, f=v


To find the focal length of the lens he should know the image distance, which is the distance between the lens and the screen.

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