1. On a very hot day, could you cool your kitchen by leaving the refrigerator door open?

(a) Yes, but it would be very expensive.

(b) Yes, but only if the humidity is below 50%.

(c) No, the refrigerator would exhaust the same amount of heat into the room as it takes out of the room.

(d) No, the heat exhausted by the refrigerator into the room is more than the heat the refrigerator takes out of the room.

2. Which of the following possibilities could increase the efficiency of a heat engine or an internal combustion engine?

(a) Increase the temperature of the hot part of the system and reduce the temperature of the exhaust.

(b) Increase the temperatures of both the hot part and the exhaust part of the system by the same amount.

(c) Decrease the temperatures of both the hot part and the exhaust part of the system by the same amount.

(d) Decrease the temperature of the hot part and increase the temperature of the exhaust part by the same amount.

(e) None of the above; only redesigning the engine or using better gas could improve the engine's efficiency.