When both jaws of vernier callipers touch each other, zero mark of the vernier scale is right to zero mark of main scale, 4th mark on vernier scale coincides with certain mark on the main scale. While measuring the length of a cylinder, observer observes 15 divisions on main scale and 5th division of vernier scale coincides with a main scale division. Measured length of cylinder is mm. (Least count of Vernier calliper = 0.1 mm)
- 15.5
- 15.4
- 15.9
- 15.1
Answer
(4) 15.1
Solution
The vernier zero lies to the right of the main-scale zero, the zero error is positive.
Zero error = +4 LC = +4 0.1 = +0.4 mm
Observed reading = MSR + n LC
= 15 + 5 0.1 = 15.5 mm
Measured (corrected) length = Observed reading - Zero error
= 15.5 - 0.4 = 15.1 mm
Answer: (4)