A screw gauge of pitch 0.5 \mathrm{~mm} is used to measure the diameter of uniform wire of length 6.8 \mathrm{~cm}, the main scale reading is 1.5 \mathrm{~mm} and circular scale reading is 7 . The calculated curved surface area of wire to appropriate significant figures is :
[Screw gauge has 50 divisions on its circular scale]