Case 1: A spherometer has a least count of 0.005mm and its head scale is divided into 200 equal divisions. Let the distance between consecutive threads on the spherometer screw be d1 mm.
Case 2: A vernier calipers has each division on its main scale to be 1mm. On vernier scale, 99mm is divided into 100 division. Let the vernier constant be d2 mm.
Case 3: The pitch of a screw gauge is 1mm and there are 100 divisions on its circular scale. When no article is placed in between its jaws, the zero of the circular scale coincides with the reference line. When a steel wire is placed between the jaws, two main scale division are clearly visible and 67 divisions on the circular scale are observed. Let the diameter of the wire be d3 mm.
The values of d1, d2 and d3 are: