gdbusher
Last Activity: 9 Years ago
the resistance of the filament in the bulb is high, the quantity of heat produced is also high. Therefore, the filament is heated to incandescence and emits light. Tungsten with a high melting point (3380oC) is used as the filament. The filament is usually enclosed in a glass bulb containing some inert gas at low pressure. Electric arc and electric welding also work on the principle of heating effect of current. In some cases such as transformers and dynamos, Joule heating effect is undesirable. These devices are designed in such a way as to reduce the loss of energy due to heating.