If you replaced the tungsten filament of a typical incandescent bulb with an iron filament, would the emission spectrum be the same?

the electrons change their energy states and photons in visible spectrum (and infrared spectrum) are emitted.More the losses, more would be the light, but at the same time, more would be the heat generated.So this necessitates that the metal used should have high resistivity (and hence high losses), good thermmal conductivity and high melting point.

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The most plausible answer is b, duration. the given amount of time is considered how long it last for.