An electronic device dissipating $30$ W has a mass of $20$ g and a specific heat of $850$ J$/$kgK$.$ The device is lightly used, and it is on for $5$ min and then off for several hours, during which it cools to the ambient temperature of $25$C$.$ Determine the highest possible temperature of the device at the end of the $5-$min operating period. What would your answer be if the device were attached to a $0\mathrm{.}2-$kg aluminum heat sink? Assume the device and the heat sink to be nearly isothermal.