Question

write out the difference between the radiation emitted from a tungsten filament and a nichrome filament. which is hotter

Answer 1

Thanks for sending us two great questions this week! Your observation about Nichrome having a much higher resistivity than Tungsten is a very good one.

However, when choosing a material for a particular application, many different properties of materials must all be considered together (such as: melting point (MP), boiling point (BP), thermal conductivity, electrical resistivity, cost, etc.). For example, while Nichrome does have a much higher resistivity than Tungsten, Tungsten has a much higher melting point than Nichrome (Nichrome MP = 1400 C, Tung MP = 3422 C). For a typical incandescent light bulb, the Tungsten filament operates at approximately 2500 Celsius; notice that this is actually above the melting point of Nichrome!

Therefore, when you compare the melting points of the materials to the operating temperatures of a light bulb, you can quickly see why Tungsten is the preferred choice for filament wires. I hope that this helps answer your question, and we hope to hear from you again soon!