The pitch of a screw gauge is and there are 100 divisions on circular scale. When faces A and B are just touching each other without putting anything between the studs 32 nd division of the circular scale coincides with the reference line. When a glass plate is placed between the studs, the linear scale reads 4 divisions and the circular scale reads 16 divisions. Find the thickness of the glass plate. Zero of linear scale is not hidden from circular scale when A and B touches each other.
Least count (L C)
= 0.01 mm
As zero is not hidden from circular scale when A and B touches each other. Hence, the screw gauge has positive error.
Linear scale reading
Circular scale reading
Measured reading
Absolute reading = Measured reading -e
Therefore, thickness of the glass plate is .