Two full turns of the circular scale of a screw gauge cover a distance of `1mm` on its main scale. The total number of divisions on the circular scale is `50`. Further, it is found that the screw gauge has a zero error of `- 0.03mm`. While main scale reading of `3mm` and the number of circular scale divisions in line with the main scale as `35`. the dimeter of the wire is

Options

A. 3.32 mm
B. 3.73 mm
C. 3.67 mm
D. 3.38 mm

Answer

D

Explanation

Least count of screw gauge `=(0.5)/(50)mm=0.01 mm`
`therefore" Reading"=["Main scale reading"+"circular scale reading"xxL.C]-("zero error")`
`=[3+35xx0.01]-(-0.03)=3.38mm`