Analyse the following observation table showing variation of image distance ( )v with object distance u in case ofa convex lens and answer the questions that follow without doing any calculations:S.No. Object distance u ( )cm Image distance v ( )cm1. -100 +252. -60 +303. -40 +404. -30 +605. -25 +1006. -15 +120(i) What is the focal length of the convex Lens? Give reason to justify your answer.(ii) Write the serial number of the observation which is not correct. On what basis have you arrived at thisconclusion?(iii) Select an appropriate scale and draw a ray diagram for the observation at S.No.2. Also find the approximatevalue of magnificatio

(i) The focal length of the convex lens can be determined using the lens formula, which is 1/f = 1/v - 1/u. However, without doing any calculations, we can observe that as the object distance decreases, the image distance increases. This suggests that the lens has a positive focal length. The exact value cannot be determined without calculations.

(ii) The serial number of the observation which is not correct cannot be determined without doing calculations. However, we can say that if the value of 1/v - 1/u is not constant for any observation, then that observation is incorrect.

(iii) To draw a ray diagram for the observation at S.No.2, we can use the following scale: 1cm = 10cm. This means that the object is placed 6cm (representing -60cm) to the left of the lens (as the distance is negative), and the image is formed 3cm (representing +30cm) to the right of the lens (as the distance is positive). The magnification can be found by taking the ratio of the image distance to the object distance. However, without doing calculations, we can say that the magnification is positive as the image is formed on the opposite side of the object.