$($a$)$ Define sensitivity drift and zero drift.

$($b$)$ What factors can cause sensitivity drift and zero drift in instrument characteristics?

$[4]$

$($c$)$ A load cell is calibrated in an environment at a temperature of $21C$ and has the following deflection$/$load characteristic shown in Table Q$1($a$)$ below:

Table Q$1($a$)$

$\backslash$table$[[$Load $(kg),0,50,100,150,200],[$Deflectiok $(mm),0\mathrm{.}0,1\mathrm{.}0,2\mathrm{.}0,3\mathrm{.}0,4\mathrm{.}0]]$

When used in an environment at $35C,$ its characteristic changes as shown in Table Q$1($b$)$ below:

Table Q$1($b$)$

$\backslash$table$[[$Load $(kg),0,50,100,150,200],[$Deflection $(mm),0\mathrm{.}2,1\mathrm{.}3,2\mathrm{.}4,3\mathrm{.}5,4\mathrm{.}6]]$

$($i$)$ Determine the sensitivity at $21C$ and $35C.$

$4$

$($ii$)$ Calculate the total zero drift and sensitivity drift at $35C.$

$[4]$

$($iii$)$Hence determine the zero drift and sensitivity drift coefficients $($in units of $\frac{m}{}C$ and per kg$\frac{\text{:}}{C}.$

$[4]$