List four precautions which a student should observe while determining the focal length of a given convex lens by obtaining image of a distant object on a screen.
CBSE 31-1-1 PAPER SET 2019
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Following are the precautions while making the image by hte help of convex lens:
- Fix the convex lens vertically in the lens holder.
- The base of the lens and white screen should be in a line with the measuring scale.
- Record the position of the lens and screen only when a well defined sharp image is formed.
- There should not be any obstacle in the path of the convex lens.
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