Question

In a screw gauge, $5$ complete rotations of circular scale give \$1.5mm$ reading on linear scale. Circular scale has $50$ divisions. The least count of the screw gauge is $x\times {10}^y$$\left(mm\right)$. Find $(x+y)$.

Answer 1

Pitch: In a screw gauge, the pitch is defined as the distance travelled in one rotation of screw.
Linear distance covered in $5$ rotations $=1.5mm$
Pitch $=\frac{1.5}{5}=0.3mm$
There are $50$ circular scale divisions.
Then, least count $=\frac{0.3}{50}=0.006$
It can be written as $6\times {10}^{-3}$
Compare it with $x\times {10}^y\left(mm\right)$.
we get,
$x+y=6-3=3$
Final Answer: $3$