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How hot does a filament light bulb get?
Hot, really hot. Typically in the range of about 2000C to 2500C (3600F - 4500F). It would be pretty difficult to directly measure the temperature of the filament so you have to use something other than a thermometer for the measurement. It should be possible to estimate the temperature of the filament from the light spectrum. Basically, treat the light bulb like a perfect black body radiator and use Plank's Law (http://en.wikipedia.org/wiki/Planck%27s_law) and the light spectrum of the bulb (for example http://www.graphics.cornell.edu/online/measurements/source-spectra/index.html) to calculate the temperature. Another way, which is a bit easier, is to use basic electronic theory to calculate the temperature of the filament that is required to produce the manufacturer's specifications for the bulb. For example, consider a typical 100 watt, 120 VAC light bulb with a tungsten filament. The bulb consumes (and radiates) 100 watts of power. A light bulb is a purely resistive load so Power=(Voltage)*(Current). Plugging in 100 watts as the power, 120 as the voltage (actually, that's the RMS voltage), and solving for current we get an RMS current of 0.83 amps. Since the bulb is just a resistor it obeys Ohm's Law; Voltage=(Current)*(Resistance). Our voltage is 120 and we determined the current to be 0.83 amps, so the resistance of the bulb when it is operating is 120/0.83= 144 ohms. If you take a 100W incandescent light bulb and measure its resistance at room temperature you get a value of about 15 Ohms. The difference between the room temperature resistance and the resistance when the bulb is operating is due to the affect of temperature on the filament's resistance. Metals (and conductors in general) increase their resistance as they are heated. The resistance at a particular temperature can be calculated with; R=Rref*(1 + alpha(T-Tref)] Where, R is the resistance at temperature T degrees Celsius. Rref is the resistance at a standard temperature Tref (often 0C or 20C). Alpha is the "temperature coefficient of resistance" for the material. For tungsten alpha=0.0044/C with a Tref of 20C (68F). If we assume that the 15 Ohm resistance at room temperature is close enough to the value at 20C (68F) then we can use Rref=15 ohms and R is the 144 ohms we calculated from the wattage and voltage of the bulb. Plugging these numbers into the equation; 144=15*(1 + 0.0044*(T - 20)) Solving for T (the temperature required to get the filament's resistance to 144 ohms) we get T=1975C (about 3600F). That's pretty hot! The filaments temperature will change if the applied voltage changes. The temperature will also be different from light bulb to light bulb (even if they have the same voltage and wattage ratings) since no two bulbs are exactly alike. An individual bulb will also change as it ages and as a function of the temperature outside the bulb.
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An incandescent bulb.
the filament is the metal peice in a bulb that glows.Tungsten is most often used in a lightbulb.
Tungsten (W) or wolfram, doped frequently with thorium oxide.
Incandescent light bulbs have filaments which are made mainly from the element tungsten and/or alloys which include tungsten. Tungsten is the metal element used for …the filaments in incandescent light bulbs. Experiments were made with different materials to use as the filament, including natural fibres, pure metals and alloys of different metals, to find the material which had the longest life whilst glowing brightly enough to give out visible light. The metal Tungsten was found to be the best, because of its high melting point (almost 3700 K) and good resistance to electrical current. For more information see the answer to the Related Question shown below. Carbonized cotton was originally tried, and had moderate success. However, the material that finally worked the best was a filament made of tungsten, which shone brighter and lasted much longer. It is made up of Tungsten which have an melting point of 3380 degree Celsius.
The filament in a light bulb generates heat from the electrical current being drawn through the lamp and that heat is what creates the light shining out of the bulb.
It is the extremely thin wire inside the bulb. It is so thin that when the electricity goes through produce light, when that filament breaks the bulb is not good.
about 10% the filament light bulbs give off about 90% heat and 10% light
Filament of bulb is made up of Tungsten. perfect answer: filament of bulb made of tungsten because of its melting point tungsten s m.p. is 3422 c and it produces through a… method called extrusion process and due to its high melting point it do not melt due to heat. thnx if any1 have some general knowledge plz send me at email@example.com Tungsten.
Most 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.
The filament inside is heated. Once it gets hot enough, it dissipates some of the energy as heat and light.
Its time to buy a new light bulb!! The filament may cool off too fast or heat up too quickly and break. When the filament is broken it stops the circut of electricty, therefor…e the bulb will not illuminate.
The metal tungsten is used for the filaments in incandescent bulbs. It has a high melting point and retains its strength when heated. The tungsten's resistance makes it glow w…hite-hot, and inert gases (mostly nitrogen) in the bulbs keep the tungsten from oxidizing.
The brightness of a light bulb is determined by its filament's watts. This is only the case with incandescent light bulbs - LED and fluorescent bulbs operate differently.
Usually a Tungsten alloy.
Filaments in incandescent bulbs are usually around 3000º C or 5000º F.
An electric current flows through the filament which is usually made of tungsten because its melting point is the highest of all metals. The filament heats to around 3000 …degrees C and becomes incandescent, radiating heat and light by what is technically called black body radiation.