Question

The circular scale of a screw gauge has 50 divisions and pitch of 0.5 mm. Find the diameter of the sphere. Main scale reading is 2.

• A. 1.2 mm
• B. 1.25 mm
• C. 2.22 mm
• D. 2.25 mm

Answer 1

The correct option is D 2.25 mm

Pitch of the circular scale $P=0.5mm$
Number of divisions on circular scale $N=50$
So least count of screw gauge L.C $=\frac{P}{N}=\frac{0.5}{50}mm=0.01mm$
Now, main scale reading is given as M.S.R $=2mm$
Marking on circular scale $n=25$
Thus, diameter of sphere $d=M.S.R+n\times L.C$
$⟹d=2mm+25\times 0.01mm=2.25mm$
Thus option D is correct.