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What must happen to the voltage and resistance for the circuit to get cold?
Wiki User
∙ 8y ago
For the circuit to get cold it must include a reversed junction thermocouple like in an electrical thermocooler.
Wiki User
∙ 8y ago
Emma Padgett
Armond Harper
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Armond Harper
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What is the relation between load and resistance?
A load is anything that draws current from a source of potential difference. A 'heavy' load will draw a larger current than a 'light' load. A resistor can certainly be used as a load. A low resistance will draw a larger current than a higher resistance and, so, a low resistance represents a high load while a high resistance represents a low load.
What is the resistance of a fuse bulb?
A lamp has two resistances: a 'hot' resistance (its operating resistance) and its 'cold' resistance (its resistance when switched off), and the hot resistance is significantly higher than its cold resistance.You can calculate its 'hot' resistance from its rated power and its rated voltage (assuming that it is being supplied at its rated voltage), by manipulating the following equation, to make Rthe subject: P= V2/RYou will, though, have to measure its cold resistance.
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.
Would you show me a diagram of a series circuit?
Diagrams are not supported with WikiAnswers, sorry, so you will have to use your imagination...A simple series circuit can be built with a battery, a switch, and a light bulb. One end of the battery is connected to one end of the switch. The other end of the switch is connected to one end of the bulb. The other end of the bulb is connected to the other end of the battery.If the switch is open, no current flows, and the bulb does not illuminate. If the switch is closed, current flows, and the bulb illuminates. By Ohm's law, the current through the bulb is proportional to the battery voltage and inversely proportional to the resistance of the bulb. Note, of course, that we are talking about hot resistance of the bulb, because cold resistance is an entirely different thing, due to the temperature coefficient of the bulb. Also, by Kirchoff's current law, the current at every point in this simple series circuit is the same and, by Kirchoff's voltage law, the voltage across the battery is the same as the voltage across the bulb.
How much resistance must be placed in a 110 volt circuit in order to limit the current to 2 amps?
Ohm's Law: Resistance = Voltage divided by current110 volts / 2 amperes = 55 ohmsNote: This represents 220 watts, which is a considerable amount of power for a resistor. In all likelihood, the resistance will change as a result of that amount of power (heat) so the end result, 55 ohms, is only valid as an absolute number, in that 55 ohms is the answer, but the cold value of the resistor is uncertain.
Does increasing the resistance increase the electric current?
If the current through a pure metallic conductor causes the temperature of that conductor to rise, then its resistance will increase. A practical example of this is an electric lamp. The cold resistance of a lamp is very much lower than the hot resistance.
What is the relation between load and resistance?
A load is anything that draws current from a source of potential difference. A 'heavy' load will draw a larger current than a 'light' load. A resistor can certainly be used as a load. A low resistance will draw a larger current than a higher resistance and, so, a low resistance represents a high load while a high resistance represents a low load.
I need to draw a circuit diagram to show this but I have no idea how do you find the resistance of a lamp in a circuit?
If you have a lamp, you can assume that the resistance of the lamp when it is under power will follow the ohms law. BUT, one thing you must remember is, when a lamp is under load, it is glowing HOT. When metal is HOT, the molculoes of the meals are in much more active state. When this happens, the resistance will increase. Conversely, when the lamp is NOT on ON state, the filaments are cold. Moleculoes in the filaments are not as active. Thus, the resistance is lower. There is almost 10 to 1 difference in resistance from hot to cold. Taking out a multimeter and measuring the resistance of the lamp will not help you determine the resistance of the lamp when it is actually under load (with voltage applied) Really, the only thing you can do is to measure the voltage, measure the current, then arrive at the resistance mathmatically.
How does the electrical resistance of an object change - If a light bulb has X ohms of resistance three of those light bulbs in the same circuit in series have less resistance?
The resistance of a light bulb is inversely proportional to its temperature, i.e. a cold bulb has less resistance than a hot bulb. As a result, if you connect three bulbs in series to the same voltage used for one, they will each receive one third of the original voltage, causing them to use less power, causing them to generate less heat, causing them to have less resistance. If you measure the current in the circuit, there will be slightly more than one third of the original current. Given the same voltage, that means that each bulb has less resistance than originally measured, as expected. This characteristic of light bulbs is why they tend to blow out at turn-on. The starting current and power is higher than in the steady state case. You can make a bulb last much longer if you provide a soft start circuit that ramps up the voltage over a short period of time.
What is the resistance of a fuse bulb?
A lamp has two resistances: a 'hot' resistance (its operating resistance) and its 'cold' resistance (its resistance when switched off), and the hot resistance is significantly higher than its cold resistance.You can calculate its 'hot' resistance from its rated power and its rated voltage (assuming that it is being supplied at its rated voltage), by manipulating the following equation, to make Rthe subject: P= V2/RYou will, though, have to measure its cold resistance.
What is voltage of a circuit with 15 amps of current andtoaster with 8ohms of resistance?
V=I*R Where: V is voltage I is the current in ampers R is resistance in ohms. So, if the current is 15 A and the resistance is 5 ohms, then the voltage must be 15 A *5 ohms = 75 V.
Why powerful lamps have lower resistance than less powerful lamps?
Power is voltage squared, divided by resistance (P = V2/R) so, for a given voltage, the lower the resistance, the greater the power!
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.
Would you show me a diagram of a series circuit?
Diagrams are not supported with WikiAnswers, sorry, so you will have to use your imagination...A simple series circuit can be built with a battery, a switch, and a light bulb. One end of the battery is connected to one end of the switch. The other end of the switch is connected to one end of the bulb. The other end of the bulb is connected to the other end of the battery.If the switch is open, no current flows, and the bulb does not illuminate. If the switch is closed, current flows, and the bulb illuminates. By Ohm's law, the current through the bulb is proportional to the battery voltage and inversely proportional to the resistance of the bulb. Note, of course, that we are talking about hot resistance of the bulb, because cold resistance is an entirely different thing, due to the temperature coefficient of the bulb. Also, by Kirchoff's current law, the current at every point in this simple series circuit is the same and, by Kirchoff's voltage law, the voltage across the battery is the same as the voltage across the bulb.
How is the resistance value for a linear resistance changed?
The resistance value for linear resistance is changed by changing the wavelength of the current or by installing additional resistors in the circuit. This restricts the amount of electricity which flows through the wiring.The resistance value for the linear resistance can be changed through strain over time. It can also be changed by changes in temperatures, such as going from hot to cold.
Can an overhead conductor carry more current on a cold day as compared to a hot day?
The only limit on how much current the conductor can carry, regardless ofthe weather, is the amount of current that causes the conductor to melt.The current in such a conductor depends on the voltage between its ends,and on the resistance of the conductor. The resistance of the conductor issomewhat less when it's cold, so a given voltage would result in more current.
There is a current of 0.83 A through a light bulb in a 120 V circuit What is the resistance of this light bulb?
If a lightbulb has a resistance of 250 ohms, the voltage required for the bulb to draw a current of 0.5 A is 125 V. (Ohm's law: voltage equals current times resistance)Unfortunately, its more complicated than that...Is the resistance of 250 ohms the hot resistance or the cold resistance? It matters. It matters very much.Light bulbs have a dramatic positive resistance to temperature coefficient. It is not uncommon for the instantaneous on power to be 10 or 20 times the nominal value.So, if the 250 ohms is the measured resistance while operating at a current of 0.5 A, then 125 V is the correct answer. If the resistance is the cold resistance, you need to go back and find out the hot resistance at the desired operating point.
