WAEC Physics 2012 Theory — Question 7

Model answer

Cold, dense air from the air conditioner sinks, while warm air (being less dense) rises. If the air conditioner is installed near the ceiling, the cold air it produces will sink down through the room, displacing the warmer air upward, setting up a convection current that cools the entire room efficiently. If it were installed near the floor, the cold air would simply stay near the floor without effectively circulating and cooling the whole room.