A screw gauge having 100 equal divisions and a pitch of length 1 mm is used to measure the diameter of a wire of length 5.6 cm…

Q: A screw gauge having 100 equal divisions and a pitch of length 1 mm is used to measure the diameter of a wire of length 5.6 cm. The main scale reading is 1 mm and 47th circular division coincides with the main scale. Find the curved surface area of the wire in cm2 to appropriate significant figures. (Use π = 22/7)

Sol. Least Count = (1 mm)/100 = 0.01 mm

Diameter= MSR + CSR(LC)

=1 mm + 47(0.01)mm =1.47 mm

Surface area = π Dl = 22/7 × 1.47 × 56 mm2

=2.58724 cm2 = 26 cm2