Incandescent light bulbs have been phased out in the US because they are very inefficient (i.e., they produce a very large amount of heat). A 10 W light-emitting diode lamp (LED) can produce about the same light output as incandescent light bulbs (about 750 lumens), but produce much less heat. Suppose a 10 W LED is placed in a 100 m^3 room.
A. Write an energy balance for the room in words. Treat the LED as a source of energy (like a utilization rate). Assume the room is insulated.
B. Calculate the J/s given off by the LED lamp. For visible light, 1 W is about 68 lumens.
C. Calculate the change in temperature of the air in the room over 8 hours. The density of air is 1.2 g/L. The heat capacity of air s 1.004 J/g - degrees Celsius.