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Q: Why does the resistance of a filament depend on the current?
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When the bulb is the resistance what this tells about the resistance?

An incandescent bulb has a filament that has a resistance. The value of the resistance determines the current that will flow for a given supply voltage. The heat generated by the current flowing through the filament gives off light. As the resistance of the filament decreases the current increases and you get more light.


Does resistance depend upon current?

The higher the resistance the lower the current flow. It restricts the flow of electrical current. The resistance will not depend upon the current. The current flow will depend on the resistance.


Does a lamp with a thick filament draw more or less current than a lamp with a thin filament?

A lamp with a thick filament will draw more current. What restricts the current flow in the filament is the resistance of the filament which increases as the temperature of the filament increases. A thin filament requires less energy to get heated up that a thick one so less current to achieve threshold resistance. Also a thick filament provides a broader path for current so there is less resistance per increase in degree centigrade. For these two (closely related but distinct) reasons it will require more current for the filament to get heated up to threshold resistance.


Does a lamp with a thick filament draw more current or less current than a lamp with a thin filament?

A lamp with a thick filament will draw more current. What restricts the current flow in the filament is the resistance of the filament which increases as the temperature of the filament increases. A thin filament requires less energy to get heated up that a thick one so less current to achieve threshold resistance. Also a thick filament provides a broader path for current so there is less resistance per increase in degree centigrade. For these two (closely related but distinct) reasons it will require more current for the filament to get heated up to threshold resistance.


Why does the resistance of a filament bulb depend on the current in the bulb?

The resistance of a piece of wire changes with temperature. In a filament bulb the wire is heated to about 3000 degrees C so a large change in resistance can be expected. A 240 v 105 w halogen bulb has a cold resistance of 35 ohms, but when running its resistance is 549 ohms.


Is the resistance lower if you have a high current?

Lower than what? For the same voltage, a lower resistance means higher current. But beware, the voltage itself might depend on the current - thus - with a fixed resistance if you change the voltage, you will increase the current in the same proportion. Some things become higher resistance if they get hot (a tungsten filament in a lamp). Other things become lower resistance if they get hot (semiconductors). So it can all depend on what kind of circuit you have.


What happens to the current in a filament is replaced by a longer wire?

resistance increases


Why is the filament inside an electric lamp made very fine?

The filament is fine so that its electrical resistance can be quite high. It is also long, for the same reason. Usually it is coiled up to fit the length in the lamp. The heating effect of electric current is proportional to the current squared, time the resistance (I*I*R). Most of the effect is due to the current. The current through the filament must be limited to stop it melting. Adding resistance will do that. Taking resistance away increases heating. So, a low energy lamp has a very thin filament and a high energy lamp will have a thicker filament.


WhY does a filament lamp get when you us high voltage?

because there is a correlation between resistance and voltage and current. The equation resistance = voltage divided by current shows that the higher the voltage, the bigger the resistance,, and the bigger the resistance the hotter the filament lamp will get because of the electrons bumping into each other which means there is a loss of energy and that energy is being transferred to the filament making the actual filament bulb hot since there is more thermal energy wasted at the end.


What is nonlinear resistance?

A nonlinear resistance is a resistance which is different for different voltages ie current is not proportional to voltage. An example of this is the filament of an incandescent lamp.


What is the purpose of the filament inside the light bulb?

The filament is a special metal composition of tungsten that conducts current and heats up and emits light as a result of the current and its internal resistance.


What was a resistance invention?

The incandescent light bulb. The tungsten filament lights due to it's resistance of the current flowing through it.