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Metals heat up as electrical currents flow through them. Cold resistance is the metals resistance before it is operating. Hot resistance is the metals resistance after operating time has elapsed some.
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Why the wires leading to an electric iron remains cold while the element gets hot?
This happens because wire have less resistance.
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.
What has more resistance hot air or cold air?
Cold air is more dense, thus is gives more resistance. Notice how you land when you're flying. In the winter, it's usually a smooth gradual landing. In summer, you hit the runway with much more force.
How do you transfer hot to cold and cold to hot?
when it is already hot refrigerate it and when it is already cold boil it............ o simple
Is it hot or cold when water evaporates?
hot. it is cold when it condensates.
What do you mean by 'cold resistance' and 'hot resistance'?
Metals that make up typical resistors (and many other electrical components for that matter) tend to heat up as current flows through them. "COLD" resistance is the resistance before it is operating and "HOT" resistance is the resistance after some operating time has elapsed.
How does temperature affect resistance of a wire?
If you are asking if a hot wire has a greater resistance than a cold wire then the answer I would say is yes. Cold wires have always had less resistance than hot wires
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.
Cold and heat fatigue resistance?
Cold and heat fatigue is one of the main forms of failure of hot work dies, and the molds for supporting pictures should have high resistance to cold and heat fatigue.
Can hot air or cold air effect how far a person hits a golf ball?
Yes, in hot air the air is a lot thinner so there is less resistance compared to cold air which is a lot denser so more resistance.
How do you check the temperature sensor on a 1989 Ford F150?
The sensor can be checked for resistance with an ohm meter. The sensor can be checked while cold then hot for resistance change.
What is Hot Resistance?
Hot resistance is your total resistance you can have with out exceeding your wattage limit
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.
How much current is needed to light a bulb with 180 ohms of resistance using 120 volt power source?
V = I x R so current I = 1/2 amp. I bet the bulb is rated at 60 W because Watts = Current x Voltage. Where V = voltage (volt) I = current (ampere) R = resistance (ohm) Your question isn't easy to answer. A lamp has two 'resistances': a 'cold' resistance, and a 'hot' resistance. Before it is energised, it is cold, so its resistance is low; when it is energised, it becomes very hot, and its resistance increases significantly. So, the question is whether your '240 ohms' is the cold resistance or the hot resistance. If it is the cold resistance, then a current of 0.5 A will flow through it for a fraction of a second, then its resistance will increase significantly, and the current will fall to a very much smaller value.
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.
Why the wires leading to an electric iron remains cold while the element gets hot?
This happens because wire have less resistance.
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.
