It is desirable to model a battery by its Thevenin equivalent. To do this, two precision resistors are used. In particular, a 25 Ohm resistor gives a 20 V drop and a 15 Ohm resistor gives a 15 V drop. The Thevenin's equivalent resistance is most nearly 1. 100 ohms
2. 75 Ohms
3. 25 Ohms
4. 15 Ohms
5. 40 Ohms

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.