he pitch of a screw gauge is 1 mm and there are 100 divisions on its circular scale. When nothing is put in between its jaws, the zero of the circular scale lies 6 divisions below the reference line. When a wire is placed between the jaws, 2 linear scale divisions are clearly visible while 62 divisions on circular scale coincide with the reference line. Determine the diameter of the wire.

To find the diameter of the wire, we need to calculate the total reading of the screw gauge which is the sum of the main scale reading and the circular scale reading.

1. First, let's calculate the least count of the screw gauge. The least count is the pitch divided by the number of divisions on the circular scale. In this case, it's 1 mm / 100 = 0.01 mm.

2. The main scale reading is the number of linear scale divisions visible multiplied by the pitch. Here, it's 2 divisions * 1 mm/division = 2 mm.

3. The circular scale reading is the number of divisions on the circular scale that coincide with the reference line multiplied by the least count. Here, it's 62 divisions * 0.01 mm/division = 0.62 mm.

4. The zero error of the screw gauge is the number of divisions below the reference line when nothing is put between the jaws, multiplied by the least count. Here, it's 6 divisions * 0.01 mm/division = 0.06 mm. Since the zero of the circular scale lies below the reference line, the zero error is negative.

5. The total reading of the screw gauge is the sum of the main scale reading, the circular scale reading, and the zero error. Here, it's 2 mm + 0.62 mm - 0.06 mm = 2.56 mm.

So, the diameter of the wire is 2.56 mm.