Problem $2.$ A transistor chip is encased in an insulating substrate. The surface of the chip $($only the top surface$)$ is exposed to the coolant flow with the constant temperature of $20$C $.$ When the chip is turned off, it is in thermal equilibrium with the coolant. When the chip is turned on$,$ however, it generates heat Q$\_($gen $)$ that is uniform throughout the volume, and the temperature of the chip increases until it reaches the steady$-$state temperature T$\_($f$).[[$Chip$,$Coolant$],[,[[-$ h$=150($W$)/($m$^(2))*$K