Analyse the following observation table showing variation of image distance (v) with object distance (u) in case of a convex lens and answer the questions that follow, without doing any calculation :

Write the serial number of that observation which is not correct. How did you arrive at this conclusion?

Explanation

Observation at S. No. (6)
The value, u = -10 cm, indicates that the object is in between the optical centre and the focus (i.e., less than the focal length) of the lens and hence the image should be on the same side as the object. The the image distance cannot be positive.