Question

A screw gauge of pitch $05 \,mm$ is used to measure the diameter of uniform wire of length $68 \,cm$, the main scale reading is $15\, mm$ and circular scale reading is $7$. The calculated curved surface area of wire to appropriate significant figures is :[Screw gauge has $50$ divisions on the circular scale]

• A. $6.8 \,cm ^2$
• B. $3.4 \,cm ^2$
• C. $3.9\, cm ^2$
• D. $2.4\, cm ^2$

Answer 1

Answer: (B)

$3.4 \,cm ^2$

Answer 2

The correct option is (B): $3.4 \,cm ^2$