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, the thickness of the wire is :
As we learned
To measure the diameter of small spherical cylindrical body using Vernier Callipers -
= 1 Main scale division - 1 V.S. Division
V.C= 1 M.S.D - 1 V.S.D
M.S.D= Main Scale Reading
V.S.D= Vernier Scale Reading
Total observed reading =
N= Nth division
1. Vernier constant (least count) of the Vernier Callipers:
1 M.S.D. = 1 mm
10 vernier scale divisions = 9 main scale divisions
i.e. 10 V.S.D. = 9 M.S.D.
1 V.S.D. = M.S.D.
Vernier Constant (L.C.) = 1 M.S.D. - 1 V.S.D. = 1 M.S.D. M.S.D.
2. Zero error: (i) ........ cm (ii) ............cm (iii) ..........cm
Mean Zero Error (e) = ............ cm
Mean Zero Correction (c) = - (Mean Zero Error)
= .......... cm