A given screw gauge has a least count of 0.002 cm and there are 50 divisons on its circular scale. When the jaws, of this screw guage, are just in contact with each other, the 7th division of the circular scale lies along its ‘reference line’.
When this scrw gauge, is used to measure the thickness of a thin mica sheet, the main scale reads 0.7 cm and the 21st division, of its circular scale, coincides with the ‘reference line’.
The ‘pitch’ of this screw gauge, and the thickness of the mica sheet, are respectively, equal to
(1) 0.2 cm and 0.717 cm
(2) 0.1 cm and 0.756 cm
(3) 0.2 cm and 0.728 cm
(4) 0.2 cm and 0.756 cm
