The correct answer is : C : 2900°C
When electric current flows through the filament, it heats the filament to a temperature of about 3000 °C (about 5000 °F), causing the filament to glow and provide light." Incandescent lamps are the most common sources of electric lighting.The tungsten filament lamp temperature is about 2800–3300 K and consists of a linear double-ended quartz tube containing a tungsten filament, which is resistively heated.
during switch-on the resistance of the lamp is increasing with temperature - so the brightness increases with decreasing current! during switch off both the brightness and the current are falling.When switched on at first the bulb filament is cold. It therefore has a low temperature. ... Otherwise that current surge could reach values of current that will produce enough heat energy to melt the filament wire.
The most common disadvantage associated with the use of filament lamp is that is can be costly to run for long periods. As mentioned before, its initial cost is low compared to other types of lighting, however, the running costs can be significantly higher than other forms of lighting.Compact fluorescent lamps are generally considered best for replacement of lower wattage incandescent lamps. These lamps have efficacy ranging from 55 to 65 lumens/Watt. The aver- age rated lamp life is 10,000 hours, which is 10 times longer than that of a normal incandescent Page 8 lamps.
You should leave the lights on because it takes more energy to turn them back on than you'll save by turning them off. FALSE! Fluorescent lights do take a small surge of power when turned on, but this is significantly smaller than the amount saved by turning them off.