A screw gauge gives the following reading when used to measure the diameter of a wire.
Main scale reading : $0\ mm$
Circular scale reading : $52\ divisions$
Given that $1\ mm$ on main scale corresponds to $100$ divisions of the circular scale. The diameter of wire from the above data is:
$0.052$ $cm$
$0.026$ $ cm$
$0.005$ $ cm$
$0.52$ $ cm$
If in a Vernier callipers $10 \,VSD$ coincides with $8 \,MSD$, then the least count of Vernier calliper is ............ $m$ [given $1 \,MSD =1 \,mm ]$
The diameter of a spherical bob is measured using a vernier callipers. $9$ divisions of the main scale, in the vernier callipers, are equal to $10$ divisions of vernier scale. One main scale division is $1\, {mm}$. The main scale reading is $10\, {mm}$ and $8^{\text {th }}$ division of vernier scale was found to coincide exactly with one of the main scale division. If the given vernier callipers has positive zero error of $0.04\, {cm}$, then the radius of the bob is $...... \,\times 10^{-2} \,{cm}$
Answer the following :
$(a)$ You are given a thread and a metre scale. How will you estimate the diameter of the thread ?
$(b)$ A screw gauge has a pitch of $1.0\; mm$ and $200$ divisions on the circular scale. Do you think it is possible to increase the accuracy of the screw gauge arbitrarily by increasing the number of divisions on the circular scale ?
$(c)$ The mean diameter of a thin brass rod is to be measured by vernier callipers. Why is a set of $100$ measurements of the diameter expected to yield a more reliable estimate than a set of $5$ measurements only ?