Question $3[20]$

$3\mathrm{.}1$ A dial test indicator $($also called DTI, Dial Gauge or Clock$)$ is a precision and delicate instrument that has a plunger projecting out of the bottom and a dial commonly graduated in incrememts of $0\mathrm{.}01$ mm $.$ Briefly discuss five uses of a dial test indicator.

$(10)$

$3\mathrm{.}2$ Figure $1$ below shows a standard $0-25mm$ metric micrometer. Name all the parts of the micrometer from $A$ to H $.$

$($b$)$

$3\mathrm{.}3$ Name two types of engineer's squares used for assessing squareness.