.Incandescent light bulbs (as contrasted with compact fluorescents and LEDs) shi
ID: 2013109 • Letter: #
Question
.Incandescent light bulbs (as contrasted with compact fluorescents and LEDs) shine because of a resistor known as a filament. When current passes through the filament, the filament heats up to very high temperatures, making it glow. Most filaments are made of tungsten.Suppose someone created a light bulb with a filament having a negative temperature coefficient of resistivity. What would happen to the resistance of the filament after the bulb was switched on and the filament began to heat up? Please explain.
Explanation / Answer
If the filament has a negative temperature coefficient of resistivity, the resistance of the filament will gradually dereased as the temperature increases. At suitable higher temperatures, the resistance of the filament almost vanishes so that all most all the current passes through the filament without loss (superconducting state). So there will be no loss of power in terms of heat or light and the filament no longer emits light nor heated up.
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.