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In a screw gauge, 5 complete rotations of the screw cause it to move a linear distance of 0 . 25 cm . There are 100 circular scale divisions. The thickness of a wire measured by this screw gauge gives a reading of 4 main scale divisions and 30 circular scale divisions. Assuming negligible zero error, what is the thickness (in mm) of the wire?

Correct answer

21.5

Step-by-step solution

Least count = 0 .25 5 × 100 cm = 5 × 10 - 4 cm Reading = 4 × 0 .05 cm + 30 × 5 × 10 - 4 cm = 0 .2 + 0 .0150 cm = 2.15 mm

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