The pitch and the number of divisions, on the circular scale, for a given screw gauge are 0.5mm and 100 respectively. When the scew gauge is fully tightened without any object, the zero of its circular scale lies 3 divisions below the mean line.
The readings of the main scale and the circular scale, for a thin sheet, are 5.5mm and 48 respectively, the trhickness of this sheet is:
5.740 mm
5.725 mm
5.950mm
5.755 mm
To measure the thickness of the given sheet using screw gauge -
1. Note the number of divisions on the circular scale.
2. Give five complete rotations to the screw.
3. Note the linear distance moved by the screw.
4. Find the pitch and L.C. of screw gauge.
5. Find the zero error and zero correction by moving the screw only in one direction in such a way that studs A and B just touch each other.
6. Now grip the given sheet in the gap A and B of the screw gauge.
7. Turn the screw head till the ratchet arrangement gives a click.
8. Note the readings of linear scale and circular scale and find the observed thickness using the relation, observation thickness = L.S.R. + C.S.R.
9. Add the zero correction to the observed thickness to find the corrected diameter.
10. Repeat steps 6 to 9 to find the thickness from four more different places.
- wherein
Total reading
= M.S.R + C.S.R
=
L.C = least count
C.S.R = Circular scale reading
A B
m 2m
R 2R
TA TB
T = kinetic energy
So
V0 = orbital velocity =
Reading = MSR + CSR - (+ ve error)
= 5.5 + 0.24 - 0.015
= 5.725 mm
5.740 mm
Option 2)
5.725 mm
Option 3)
5.950mm
Option 4)5.755 mm
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