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The filament of a light bulb isn't like a resistor ... it is a resistor. The only difference from the ones on circuit boards is the it's designed to operate at a much higher temperature. So hot that it glows. The glass envelope is there to prevent oxygen from getting in and promptly burning it. When the filament becomes too hot it breaks breaking the current that was lighting it in the first place. That is why the light bulb "burns" out.
Wiki User
∙ 15y ago
Wiki User
∙ 13y agoMost simple incandescent light bulbs are made of a thin section of tungsten through which the current flows.
This section of tungsten is called a "filament".
The tungsten filament has electrical resistance and so is a resistor.
As a resistor it develops a voltage drop. This voltage drop multiplied by the amperage passing through it equals the wattage of the bulb.
The heated tungsten gets to thousands of degrees above room temperature and becomes hot enough to produce yellow-white visible light.
As a resistor, the tungsten light bulb has a positive resistance coefficient.
This means that the electrical resistance goes up when the filament becomes hot.
For example, a 100 watt light bulb operated at 120 volts - it does not matter if it is AC or DC for this calculation - will have a resistance of 144 ohms when hot and draw .833 ampere.
When cold the filament typically has a resistance of only 10 ohms which increases as the filament heats up.
An interesting note:
The typical incandescent light bulb life is between 1000 and 2000 hours.
Some "long life" incandescent light bulbs simply have a thicker but longer section of tungsten and can run 5,000 to 20,000 hours or more without failing.
This type of bulb is sold to hotels and other places that want to reduce the replacement frequency of the bulbs.
If a manufacturer desired to do so they could make a light bulb which would last even longer than 20,000 hours by increasing the filament thickness but they feel that economically it would not be desirable for them, as they would sell less light bulbs.
Wiki User
∙ 11y agoWiki User
∙ 6y agoIt is the tungsten element in a filament light bulb that is the resistor. It is this resistance that produces light and heat.
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Does the length of the wire affect the brightness of the bulb?
Wire has a certain amount of resistance. As electricity flows down the wire, some of the voltage is lost in the wire before reaching the lamp. So, the longer the wire, the less voltage the lamp gets, and the dimmer it will be.
Does fluorescent bulb act as grow light?
Plants grow well in the red end of the light spectrum. Fluorescent tubes come in many light outputs. Cool white which is in the blue end of the spectrum down to the warm white which is on the red end. Manufactures make a growlux tube which is used specifically for plant growth. Store meat counters are starting to use these tubes for display lighting as they enhance the red colouring of the meat on display.
Which wire has greater resistance a light plugged into an extension cord or a light plugged directly into a wall?
Light and an extension cord. The extension cord will act as an added resistor in series. The more cord you add will only increase the overall resistance from the wall outlet. If you use a high gage extension cord, this will help reduce the resistance. But any cord will add resistance. If the gage is low, then the cord will actually heat up and you will be able to feel the heat. That is due to the resistance within the cord. Check out my sketch of how I perceive your Q: Chord + drop light w/chord ]---------------(]--------O Versus drop light w/chord ]--------O
What convinced scientists that light is a particle?
Nothing. Scientists believe that light can act as both a particle and a wave. Look up the famous double-slit experiment.
How do light microscopes differ from election microscope?
a light microscope uses a lamp underr the microscope and an electron microscope sends a beam of electrons down to act like a magnet to suppl light to the object.
Is it correct to say that a bulb in a circuit is a resistor?
Yes it is. The filament in a standard incandescent bulb is a type of resistor. An incandescent light bulb contains tungsten which reduces electricity and converts electricity to heat and light. All incandescent bulbs are resistors, but only a fraction of resistors are bulbs. If you want to see if a bulb is a resistor, try adding another bulb in series without changing the voltage. Both bulbs will be very dim. Another way to test this is to get a multimeter and set the meter to the resistance setting. If you get any value other than zero, then it is functioning as a resistor.
What is the function of a filament?
On a standard incandescent light bulb, the glass traps a set of gases around the filament that help keep the filament from burning up quickly. (The filament is the part that does the actual glowing inside the glass.) It also keeps the oxygen in the air that we breathe away from the filament. Oxygen is one of the gases that will vastly accelerate the destruction of the filament. (Also, the glass keeps anything from touching the electrical conductors inside.) The glass can also act as a filter to remove any ultraviolet radiation caused by certain types of light bulb's ("lamp's" technically) methods of creating a arc to produce light. When specially teated, the glass can also be used to break up the light rays to cause more diffused source of light. (Think "Soft White" to get an idea.)
What is the function of the glass bulb in a bulb?
On a standard incandescent light bulb, the glass traps a set of gases around the filament that help keep the filament from burning up quickly.(The filament is the part that does the actual glowing inside the glass.)It also keeps the oxygen in the air that we breathe away from the filament. Oxygen is one of the gases that will vastly accelerate the destruction of the filament.(Also, the glass keeps anything from touching the What_is_the_purpose_of_the_glass_on_a_light_bulbconductors inside.)The glass can also act as a filter to remove any ultraviolet radiation caused by certain types of light bulb's ("lamp's" technically) methods of creating a arc to produce light.When specially treated, the glass can also be used to break up the light rays to cause more diffused source of light. (Think "Soft White" to get an idea.)
What was George Washington's role in the judiciary act of 1789?
He invented the light bulb
How capacitor act like resistor?
capacitor acts as resistor because it has some resistace alos.
What type of energy transformation occurs when a light bulb is turned on?
Electrical energy is transformed into heat and light. More specifically, electrical energy from the household wiring is turned into thermal energy (heat) by the filament which in turn becomes luminous energy (light). Some energy is lost due to resistance in the conductors.
What is the job of a bulb in a circuit?
The job of the bulb in a circuit is to convert electrical energy to light. It's called the load in the circuit.
Can a transistor can act like resistor capacitor inductor?
A transistor acts like a resistor when Gate is connected to Source.
Why can a light bulb act like a fuse?
A lamp must never be used as a fuse. But if you are asking why lamps sometimes burn out, rather like fuses do, then the reason is because if a voltage greater than its rated voltage appears across its element, its temperature may significantly exceed its design temperature, and the filament will melt.
What type of energy is turning on a light?
The light bulb uses electrical energy, and produces light, as well as waste heat. The act of turning it on in itself uses a small amount of energy stored in your muscles.
How do resistors act in parallel?
Parallel resistors act like a resistor smaller than the smallest parallel resistor. Calculate as 1/(1/R1+1/R2+1/R3...)
Can light blub act as sun and make flower?
If you use fluorescent lighting you will receive flowers on your plants. A regular light bulb will not do the trick. Buy a cheap shop light fixture and put in two long tubes one cool and one warm. Yes- artificial light can be used to grow plants, including flowers. A light bulb may not make enough light. Search for grow light or plant light.
