describes what happens to the resistance of the light bulb as the voltage is increased. Explain please as to why the resistance changes. Does it follow Ohm's Law?
Describe how the resistance of the zener diode changes as the voltage increases. Why are zener diodes not ohmic devices?
as voltage across bulb is increased then current throught filament of bulb also increases according to ohms law.
as current increases, heat produced by filament also increases. now filament being made of metal tungsten, its resistivity increases because resistivity of metal increase with temperature. so resistance of filament of bulb increases.
yes it follow ohms law.
zener diode is made of semiconductor and for semicinductor, resistivity decreases with temperature as with increase in temperature, electron in valence band gets more energy to go to conduction band. so resistance of zener diode will decrease with increase in voltage.
zener diode is not ohmic device because it is made of semiconductor and being doped with impurities, it does not obey ohms law. thats why not ohmic
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