The pitch of a Screw gauge is 1 mm and there are 100 divisions on the circular scale. While measuring the diameter of a thick wire, linear scale reads 3 mm and 46^th division of circular scale coincides with reference line. The instrument has a +ve error equal to 6 division of circular scale. Now, length of wire is measured by a vernier calipers, whose 9 divisions of main scale coincide with 10 divisions of vernier scale and one main scale division is 1 mm. For measurement of length the main scale reading is 4.5 cm and 0^th vernier divisions is found to be coinciding with main scale (Take $\mathrm{\pi }$ = 3.142)