This discussion over tungsten filaments is a little esoteric, surely?

 

The higher the filament temperature the whiter the light produced.

Tungsten is used for filaments as it has the highest melting point of any metal a bit over 3400^o K.

 

However it has a positive coefficient of resistivity with temperature so as the filament heats up the resistance rises.

This is fortutious as this means the current drops to a self limiting value.

 

The filament resistance increases to nearly 20 times its cold (room temperature) value by the time it is near melting.

Edited April 26, 20178 yr by studiot

This discussion over tungsten filaments is a little esoteric, surely?

 

The higher the filament temperature the whiter the light produced.

Tungsten is used for filaments as it has the highest melting point of any metal a bit over 3400^o K.

 

However it has a positive coefficient of resistivity with temperature so as the filament heats up the resistance rises.

This is fortutious as this means the current drops to a self limiting value.

 

The filament resistance increases to nearly 20 times its cold (room temperature) value by the time it is near melting.

That doesn't change the fact that, under operating conditions, a light bulb with a higher wattage produces more lumen and has a lower resistance.

 

If you put two light bulbs of different wattage in series, the bulb with lower wattage and thus higher resistance will shine brightest. But that's not a common situation.

The resistance of any wire depends on the collisional processes occurring within the wire. An increase in temperature causes an increase in collisions (experimental proved), means collisions and temperature are directly related and thus the resistance. The equation below provides a relationship between resistance and temperature.

so that was hope you got an idea on this.