The least count of the main scale of a vernier callipers is $$1mm$$. Its vernier scale is divided into $$10$$ divisions and coincide with $$9$$ divisions of the main scale. When jaws are touching each other, the $$7th$$ division of vernier scale coincides with a division of main scale and the zero of vernier scale is lying right side of the zero of main scale. When this vernier is used to measure length of a cylinder the zero of the vernier scale is between $$3.1cm$$ and $$3.2cm$$ and $$4th$$ VSD coincides with a main scale division. The length of the cylinder is (VSD$$ is vernier scale $$division)

Question

Infinity Learn · Accepted Answer

As zero of vernier scale is to the right of zero of main scale, error is $$+ve$$.least count $$=$$  MSD−$$VSD=0.1mmPositive$$ zero error $$=7$$×$$LC=0.7mmMeasured$$ length  $$=31mm+4L$$.$$C=31.4mm$$ $$l=31.4mm$$−$$0.7mm=30.7mm=3.07cm$$

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