A screw gauge of pitch \( 0.5 \, \text{mm} \) is used to measure the diameter of uniform wire of length \( 6.8 \, \text{cm} \), the main scale reading is \( 1.5 \, \text{mm} \) 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]
