In a Vernier calipers, when both jaws touch each other, zero of the Vernier scale is shifted to the right of zero of the main scale and 7th Vernier division coincides with a main scale reading. If the value of 1 main scale division is 1 mm and there are 10 Vernier scale divisions, then the Vernier caliper has
- 0.07 cm negative zero error
- 0.7 cm negative zero error
- 0.07 cm positive zero error
- 0.7 cm positive zero error
Answer
(3) 0.07 cm positive zero error
Solution
Least count, LC= 1 MSDnumber of VSD= 1 mm10=0.1 mm=0.01 cm
∵ With the jaws closed, the Vernier zero lies to the right of the main-scale zero, the instrument reads more than zero ⇒ the zero error is positive.
Zero error =+(coinciding VSD) =+7 0.01 cm
∴ Zero error =+0.07 cm (positive), to be subtracted from every reading.
Answer: (3)