A student focused the image of a candle flame on a white screen by placing the flame at various distances from a convex lens. He noted his observations as :
||Distance of flame from the lens (cm)
||Distance of the screen from the lens (cm)|
(a) From the above table, find the focal length of lens without using lens formula.
(b) Which set of observations is incorrect and why ?
(c) In which case, the size of the object and image will be same ? Give reason for your answer.