Q27 of 27 Page 1

List 4 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.


Add few lines about the experiment by which the focal length is calculated.


We can also add a diagram (like such these are copyright)


1. The lens should be help properly and vertically.


2. At least 3-4 observations should be taken .


3. The lens should be moved forward and backward to get a clear and sharp image on the screen.


4. The base of lens, screen and measuring scale should be in a straight line.


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