75 ohms. R = E/I.
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.
I = E/R
Well, honey, the filament lamp doesn't give a hoot about Ohm's Law because its resistance changes with temperature. As the current increases, the temperature of the filament rises, causing the resistance to also increase. It's like trying to control a wild horse - good luck getting it to follow any law!
A: Because both item are connected is series. Any resistance connected in series will carry the same current no matter of the resistance value or the number of resistors. However for an incandescence lamp the value will change when turn on and change when it is hot, That is because lamps have different property then resistance when cold and hot
While Voltage and Resistance typically remain constant in incandescent lamps: P (Power in Watts) = I (Current in Amperes) times E (Electrostatic energy in Volts [AC and DC]). P=I*E - when P (Watts) goes up so does I (Amps).
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.
The resistance of a lamp operating at 115 volts and using 0.25 amp of current is 460. The relationship I used is Ohm's law.
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.
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.
The formula you are looking for is R = E/I. Resistance is stated in ohms.
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.
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.
The relation between resistance R, Current I and voltage V is: R= V/I Therefore: 60 = 12 / I <=> I = 12 / 60 = 0.2 amp
The relationship between the voltage and resistance in a filament lamp is non-linear. As the voltage increases, the resistance in the filament of the lamp also increases due to the heating effect. This increase in resistance causes the current to increase at a slower rate than expected, leading to a non-linear slope in the voltage-resistance graph.
The lamp wire is hot because electrical current flowing through it encounters resistance, which causes the wire to heat up.
The resistance of the lamp can be calculated using the formula: Resistance = (Voltage)^2 / Power. Plugging in the values gives: Resistance = (120 V)^2 / 120 W = 120 ohms. So, the resistance of the 120-W incandescent lamp connected to a 120-V power supply is 120 ohms.
0.02 amperes