Filament Definition and 69 Threads

An infinite current filament carries a current of 3A and lies along the x-axis. Using Biot-Savart Law, find the magnectic field intensity in cartesian coordinates at a point P(-1,3,2). dH = I vec{dl} x hat{R} / 4piR^2 let substitude hat{R} with vec{R} / R then dH = I vec{dl} x vec{R} / 4piR^3...

Filament of incand bulb are coiled in geomtry. cold resistance is 1/15 (aprox) of hot resistance. The coiled filament have inductance ''L". question Does the equation Ldi/dt is applicable? if so is the inrush current is limited?

The experiment is joule heating and I'm trying to calculate the filament resistance.1.) mass of the calorimeter cup 49.5g specific heat of the aluminum cup: 0.22 cal/kg*K mass of calorimeter cup w/ water 232.5g initial water temp. 20.5 C voltage across heater 7.3V current through heater 5A final...

Homework Statement I want to modelling a light bulb filament in MATLAB, but I don't know, what functions describe this shape. My question is, what are equation (x,y,z) which describe the light bulb filament.

Homework Statement A long glass filament carries a charge density \lambda = - 2.7{\rm{ nC/m}} . What is the magnitude of the electric field 0.67 mm from the filament? The Attempt at a Solution Did I do this problem correctly? I'm guessing not because my answer has an extra /m ...

Hi, does the thickness of filament affect the brightness of a bulb? So will a thinner filament be brighter than a thicker filament?

So for my physics independent study project. I am studying the resistance vs. temperature in non-ohmic material. I passed different currents through the light bulb and took the surface temperature with a thermocouple. How can I find the temperature of filament using the surface temperature...

Homework Statement what does k and n relate to? i can work them out but don't know exactly what they are. Homework Equations I=kV^n The Attempt at a Solution i think the k and n have something to do with temperature and the tungsten metal in the lamp (coefficient of resistance?)...

Hello, I have a Tungsten filament radiance source that has been calibrated in the UV region and would like to extrapolate the radiance to longer wavelengths. By calibrated, I mean, a NIST plot of spectral radiance v. wavelength at a certain set of operating conditions. I'm new to this...

Since oxidation is the reason for light bulb tungsten filament destruction in case of breach of the bulb envelope, while illuminated, what is the minimum oxygen required for oxidation to occur. Assume an automotive 12vdc bulb which has a greater diameter filament. However if it is considered...

Hi there, First post here guys! :biggrin: Recently i have been assigned my coursework on measuring the resistance of a filament lamp whereby an experiment was carried out by increasing the voltage through the filament lamp in intervals of 0.5 volts and measuring the current. I have since made...

From wikipedia: A filament lamp obeys ohms law within certain limits of voltage and current so does that mean it is an ohmic device? Also from wikipedia: Sounds reasonable as well. Im inclined to believe the second quote since there are only a few values that the filament lamp will...

Hi, I am stuck on this question, any help would be appreciated. Thanks! The tungsten filament of a certain 100 W light bulb radiates 2.85 W of light. (The other 97.15 is carried away by convection and conduction) The filament has surface area of 0.400 mm^2 and an emissivity of 0.952. Find...

Hey so I am stuck on a 2part question, it goes as follows: A tungstan filament in a light bulb is rated 75w for a 230v supply. The resistance of the filament at 20*C (*C means degrees celcius) is 68 ohm. Assume a constant temperature coefficient of 0.005. Calculate: A) The hot resistance...

Hello everyone I'm stuck on this problem it says: A common flashlight bulb is rated at 0.30 A and 2.9 V (the values of the current and voltage under operating conditions). If the resistance of the bulb filament at room temperature (20°C) is 1.4 , what is the temperature of the filament when the...

carbon filament in a light bulb does obey the ohm's law right?

I am using a Vacum filament lamp, i wanted to know will the temperature of the surface of the bulb will be same as room temp at 0V. the bulb is attached to a power supply. thanks

i am an A-Level student second year and i got this particle exam, i want some help. i wanted to know how to measure the temperature of the sureface of the lamp. What thermometer would be the best to measure the temperature and why? thank you

Hi there, can anyone pls explain why 1. the current through a filament light globe is greater in the first few milliseconds after it is turned on before it reaches it's "steady" glow? 2. is it better to have headlights in a motos vehicle connected in parallel rather than in series...