Least Count, Vernier Callipers & Screw Gauge
In an experiment to find out the diameter of wire using screw gauge, the following observations were noted:

(A) Screw moves on main scale in one complete rotation
(B) Total divisions on circular scale
(C) Main scale reading is
(D) th division of circular scale is in the pitch line
(E) Instrument has 0.03 mm negative error
Then the diameter of wire is:
Show answer and solution
Answer: (c)
- LC mm
- Observed reading mm
- Negative zero error mm, so correct reading mm
- So the answer is (c) mm.