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When the bulb is the resistance what this tells about the resistance?
Wiki User
∙ 12y ago
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.
Wiki User
∙ 12y ago
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What is meant by cold resistance of filament lamp?
It means exactly what it sounds like. The resistance of an incandescent bulb's filament depends on its temperature. A filament has a positive temperature coefficient, which means that its resistance increases as its temperature increases. A typical 40 watt bulb (120 volts) has a cold resistance of about 28 ohms, but its hot, operating resistance is about 360 ohms. If the cold resistance were constant, the bulb would dissipate 379 watts. In fact, cold turn on is the most stressful time for a bulb.
What is the resistance of a lightbulb using Ohm's law?
By Ohm's law, resistance is voltage divided by current, so the resistance of a light bulb can be measured by observing the voltage across it simultaneously with observing the current through it. Interestingly, the hot resistance is significantly different that the cold resistance, so measuring resistance with an ohmmeter will not give a meaningful resistance. This is because the resistance of a light bulb has a positive temperature coefficient. Take a typical 60 W 120V light bulb, for instance... Its cold resistance is about 16 Ohms. Calculate current and power at 120 V and you get 7.5 A and 900 W. The truth is that at 60 W, the bulb pulls 0.5 A and has a resistance of 240 Ohms.
The electrical resistance of a 100w 240v bulb will be?
42 ohm
Why is there zero current when a light bulb burns out?
there is no voltage and resistance
What a few example of non linear resistance?
Two examples of non linear resistance is a diode and a light bulb.
Which has the thickest filament - a high-resistance or a low-resistance bulb?
A low resistance bulb has a thicker filament.
What is cold resistance?
That is e.g. the resistance of a cold bulb before the bulb is lighted and heats up.
What gives the biggest resistance 3 volt bulb or 6 volt bulb?
3 volt bulb gives the biggest resistance
What does a light bulb have?
The resistance of a light bulb varies, depending on the type of bulb, the power rating, and the temperature. A typical incandescent 60 watt bulb, for instance has a cold resistance of about 30 ohms, and a hot resistance of about 240 ohms.
What is the general resistance of a tungsten filament?
The resistance of the filament in a light bulb is(voltage at which the bulb is designed to operate)2/(the rated power/watts of the bulb)
For bulbs connected in series the high watt bulb has high resistance?
No, the highest wattage bulb will have the lowest 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 material inside a light bulb a conductor or resistance?
It has high resistance.
Why does a motor have a bigger resistance than a bulb?
There is no particular reason why a motor should have a bigger resistance than a bulb. A motor's resistance must depend on what current it draws at the particular voltage it was designed to run on. Equally, a bulb's resistance must depend on what current it draws at the particular voltage it was designed to run on. A particular motor may have a higher resistance than one kind of bulb but that same motor may have a lower resistance than another kind of bulb.
Which has a higher resistance a 5w lamp bulb or a 25w lamp bulb and how many times?
As per the formula for power (Power (Watt) = Voltage (V) x Current (i) & Resistance (R) = V / i), 25w lamp bulb would have higher resistance compared to that of 5w lamp bulb.
Does the resistance of a light bulb filament change after the light has been turned on?
The electrical resistance of a light bulb increases when it is turned on 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.
What is meant by cold resistance of filament lamp?
It means exactly what it sounds like. The resistance of an incandescent bulb's filament depends on its temperature. A filament has a positive temperature coefficient, which means that its resistance increases as its temperature increases. A typical 40 watt bulb (120 volts) has a cold resistance of about 28 ohms, but its hot, operating resistance is about 360 ohms. If the cold resistance were constant, the bulb would dissipate 379 watts. In fact, cold turn on is the most stressful time for a bulb.
