$($b$)$ An electronic device is modelled with a current source Is and a parallel resistance Rs$.$ The current at the terminals of the source is measured to be $9\mathrm{.}875$ mA when an ammeter with an internal resistance of $402$ is used. Choose the value of Is and Rs such that the ammeter reading falls to $9\mathrm{.}756$ mA upon adding a $3\backslash$Kappa $\backslash$Omega resistor across the source terminals.

$($c$)$ What will the ammeter reading be if the resistance between the source terminals is changed to $5\backslash$Kappa $\backslash$Omega $?$