In a particular semiconductor material, the effective density of states functions are given by nc nc0· (t300)32 and nv nv0· (t300)32 where nc0 and nv0 are constants independent of temperature. experimentally determined intrinsic carrier concentrations are found to be ni 1.40 102 cm3 at t 200 k and ni 7.70 1010 cm2 at t 400 k. determine the product nc0 nv0 and the bandgap energy eg. (assume eg is constant over this temperature range.)

A2-m rigid tank initially contains saturated water vapor at 100 kpa. the tank is connected to a supply line through a valve. steam is flowing in the supply line at 600 kpa and 300 c. the valve is opened, and steam is allowed to enter the tank until the pressure in the tank reaches the line pressure, at which point the valve is closed. a thermometer placed in the tank indicates that the temperature at the final state is 200°c. determine (a) the mass of steam that has entered the tank (b) the amount of heat transfer.