A room with insulated walls is initially at the outdoor temperature of 21°C. The room contains a 100-W light-bulb, a 135-W TV set, a 220-W refrigerator, a 140-W fan, and a 2000-W iron. (a) Determine the total energy consumption (in kJ), when all of these electric devices are on from 12:30 pm to 4:30 pm, while the fan is off. (b) Determine the total energy consumption (in kJ), when all of these electric devices are on from 12:30 pm to 4:30 pm, while the fan is on only from 1:00 pm to 2:30 pm. (c) What can you say about the temperature of the room before and after the running of the fan?