A screw gauge gives the following readings when used to measure the diameter of a wire

Main scale reading : 0 mm Circular scale reading: 52 divisions

Given that 1 mm on the main scale corresponds to 100 divisions on the circular scale. The diameter of the wire from the above data is :

CONCEPT:

Screw gauge - A screw gauge is an instrument used to measure the diameter or thickness of a thin wire or thin metal sheet. Its least count is 0.01 mm.

For the diameter of the wire = MSR + (CSR × LC) ---(1)

Where MSR is the main scale reading.

CSR is a circular scale reading and LC is the least count.

CALCULATION:

Given that pitch of the screw gauge, P = 1 mm

Number of circular division, n = 100

Thus, least count LC =\(\frac{P}{n} = \frac{1}{{100}} = \) 0.01 mm

= 0.001 cm

Given : MSR = 0 mm

            CSR = 52 divisions

Using equation (1) we get;

The Diameter of the wire = MSR + (CSR × LC)

                                  =0 + (52 × 0.001 cm)

                                  = 0.052 cm

Hence, option 1) is the right answer.