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The answer is NO.
Ohm's law states that current (I) flowing through the conductor is proportional to the potential difference (V) developed across its ends, keeping physical conditions such as pressure, temperature, strain constant.
In a filament lamp, the heating element used is Tungsten (W) which has high melting point and resistivity. Due to which , when current passes through it gets heated up and glows producing light and heat. As more and more, current flows through it, it gets considerably heated, resulting in increase of temperature. This is against the requisite condition "constant temperature". Hence Ohm's law cannot be verified using filament lamp because the temperature varies when the current flows through it.
Wiki User
∙ 12y ago
Wiki User
∙ 11y agoNo. For a circuit element to obey Ohm's Law, the ratio of voltage to current must remain constant over a wide range of voltage variations. The ratio of voltage to current for a tungsten filament changes as the voltage varies, so it is considered to be a 'non-ohmic' or 'non-linear' device and, so, it does not obey Ohm's Law.
The resistance of the filament, at any given voltage, can be found from the ratio of voltage to current at that particular voltage -i.e. R = E/I.
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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 an electric lamp that takes in a current of 0.40 ampere when 110 volts is applied?
Ohm's Law: Resistance is voltage divided by current 110 volts divided by 0.4 amperes is 275 ohms.
Why do the reading differ for increasing and decreasing values of the lamp voltages?
at the time of decreasing lamp voltage as the temperature is already high the gas in the lamp is already in ionized state leading to different resistance ,but when increasing voltage the gas is not in ionized state it ready to ionize ,so there is slightly variation in resistance . :)
What must know to calculate current using Ohms law?
The resistance R in ohms (Ω) is equal to the voltage V in volts (V) divided by the current I in amps (A)
How much current flows through a lamp with a resistance of 60 Ohms when the voltage across the lamp is 12 V?
The relation between resistance R, Current I and voltage V is: R= V/I Therefore: 60 = 12 / I <=> I = 12 / 60 = 0.2 amp
If the tungsten filament of a lamp has a cross-sectional are of 5x10-9 m2 how long must it be have a resistance of 120 ohms at 20 degrees Celsius?
If the tungsten filament of a lamp has a cross-sectional area of 5x10-9m2,how long must it be to have a resistance of 120 ohms at 20 degree celsius?
What happen if a 110 volt lamp connected on a low voltage?
If you had a 60 watt incandescent bulb it would draw about 1/2 amp. That means that the resistance of the bulb filament would be about 220 ohms. Now if you applied 12 volts DC across 220 ohms you would draw about .05 amps. This would not be enough to heat the filament and create any useful light. Remember Ohm's Law says Volts = Amps x Ohms.
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.
Why does the filament lamp does not follow Ohms Law give any example?
A filament's resistance value varies with temperature. When directly measuring resistance, the filament is off, and at or near room temperature. When the circuit is turned on to measure voltage and current, the filament's temperature will increase and the resistance value will increase. This makes it appear as though Ohm's law is wrong.AnswerThere is no difficulty; your experiment will simply prove that the filament of the lamp doesn't obey Ohm's Law.When you plot the results of current against voltage for a lamp's filament, obtained from your experiment, the result will be a curved line, indicating that the current is notproportional to voltage (due to a changing resistance). This shows that the filament doesn't obey Ohm's Law. To obey Ohm's Law, the result must be a straight-line graph.Although the resistance of the lamp can be found at any point along the curve from the ratio of voltage to current (i.e. R = V/I) at that particular point, the lamp does not obey Ohm's Law. Ohm's Law only applies when the ratio of voltage to current remains constant throughout the experiment.So no difficulty has arisen with your experiment, you have simply proved that Ohm's Law doesn't apply to the lamp filament. Believe your results!!
Why is an incandescent lamp nonlinear?
Because the more you heat up a conductor the more it's electrically resistant. So, when you increase the supply voltage across such a lamp, the current increases as well, but it heats up the filament, which in turn lowers the current. So, its current depends on 2 variables: voltage and filament temperature. That's why you find a discrepancy between the resistance you measure with an ohmmeter and the one you calculate by using its rated power.
What is the resistance of an electric lamp that takes in a current of 0.40 ampere when 110 volts is applied?
Ohm's Law: Resistance is voltage divided by current 110 volts divided by 0.4 amperes is 275 ohms.
What difficulty will Aries while testing wheather the filament of light bulb obeys ohms law?
If you plot a graph of current against a range of voltages applied to an incandescent lamp, the result will be a curvedline. This tells us that the current is not proportional to the voltage and, so, the lamp does not obey Ohm's Law.However, the ratio of voltage to current will indicate the resistance for that particular ratio.
What is the resistance of 150-volt lamp with a current of 2amps?
75 ohms. R = E/I.
What is 12040000000000 in ohms using a metric prefix?
12.04 Ter-Ohms
Why do the reading differ for increasing and decreasing values of the lamp voltages?
at the time of decreasing lamp voltage as the temperature is already high the gas in the lamp is already in ionized state leading to different resistance ,but when increasing voltage the gas is not in ionized state it ready to ionize ,so there is slightly variation in resistance . :)
Can you use a 24 volt lamp in a 12 volt socket?
Let's say you have a 60 watt bulb. At 120 VAC that bulb will draw 1/2 amp. By Ohm's Law: Volts = Current x Resistance. Therefore, the resistance of the bulb filament is 240 Ohms. If 12 volts is applied across 240 Ohms the current = 12/240 or 1/20 of an amp. This small current will not be sufficient to heat up the filament and provide useful light. You might see a small glow in a dark room.
How do you find OHM?
Ohms can be found by using these formulas. Ohms = Volts/Amps, Ohms = (Volts (squared))/Watts, Ohms = Watts/(Amps (squared)).
