What is Bulb: Definition and 283 Discussions

1. Hi, I've got this question that's asking for the effects of increasing the size of the liquid -in-glass bulb. I think they're asking for at least 3 points. 3. L think its supposed to accentuate the increase in volume of the liquid, and it increases the time taken to measure the temperature...

Assuming equal voltage, will it burn-out an AC light bulb if I put it on a DC circuit?

Homework Statement A common flashlight bulb is rated at 0.3 A and 3.3 V (the values of current and voltage under operating conditions). If the resistance of the bulb's tungsten filament at room temperature (20.0 degrees Celsius) is 1.10 Ohms , estimate the temperature of the tungsten...

hi there, i hav few questions: 1. A 12V, 24W tungsten filament bulb is supplied with current from n cells connected in series. Each cell has an emf of 1.5V and internal resistance of 0.25. What is the value of n in order that the bulb runs at its rated power? 2. Three bulbs are rating 40W...

Homework Statement Initially the switch is closed in the circuit shown and the light bulb is shining brightly. What happens when the switch is opened? (diagram in attached link) 1. The bulb goes out immediately. 2. The bulb gets gradually brighter. 3. The bulb gets gradually dimmer...

Can a 12 volt car battery illuminate a 120vac 100 watt bulb ? I not sure if a bulb that is rated for 120 volts can still be powered with a battery pushing 12 volts. I think the 100 watt bulb only needs 1 amp to be illuminated with the 120 volts. I'm still trying to figure out the basics...

Hi all, there are a few questions regarding the incandescent light bulb, which I believe are rather elementary, but has nevertheless been bothering me for quite some time. I don't know if my chain of thought is correct, please point out my mistakes if there's any. Thanks! Here goes (they are...

Hi, Is it possible to make a standard light bulb light without any physical contact to it (appart from support)? I seem to remember seeing such an experiment, but can't remember the details. Thanks

How does one calculate efficiency for an incandescent light bulb? Assume the bulb is 40 W, has a tungsten filament at temp. ~ 2800 K. The bulb would be used for heating in a device. If we assume blackbody: From Wien's displacement law, the maximum wavelength is 9.99E-7 m. Fromt the...

Homework Statement How many Joules of energy does a 100 watt light bulb use per hour? How fast would a 70-kg person have to run to have that same amount of kinetic energy? Homework Equations How fast would a 70-kg person have to run to have the same amount of kinetic energy? The...

A 10 ohm resistor in a series with a bulb and a 12v source. a) If the 8.0V is across the bulb, what is the voltage across the resistor? I wrote 4v, is this correct? b) What is the current in the circuit? I wrote 1.5A, is this correct? c) What is the resistence of the bulb? Could...

Homework Statement A 100 W incandescent light bulb converts approximately 2.5% of the electrical energy supplied to it into visible light. Assume that the average wavelength of the emitted light is λ = 530 nm, and that the light is radiated uniformily in all directions. How many photons per...

This is my question verbatim: "If 5% of the power of a 100w bulb is radiated in the visible spectrum, how many visible photons are radiated per second?" My work:Obviously, 5% of 100w is 5w, or obviously, 5 J/s.So the bulb is emanating 5 J of visble light per second.Now, I could easily solve...

heat energy out of 500 w halogen bulb? how much heat energy is liberated out of a 500W halogen bulb??>? what temp is reached in 1 min.

Request answer for the below question: "An Electric bulb draws 2.4 amphere at 12.0 volts. What is the resistance. What happens to the resistance of the same bulb when it draws current less than that of the given value?" does the resistance decrease, increase or remain same? i was marked...

Can a halogen light bulb be powered by gas, or can a halogen light bulb only be powered by electricity? Can an incandescent light bulb be powered by gas, or can an incandescent light bulb only be powered by electricity?

Hey guys, was wondering if you could help me with this question: What determines the brightness of a lightbulb? I think it would be power (and therefor voltage and current since P = VI) as power is used in the measurement of energy delivered. Why is it the case then that, from the...

Homework Statement We did an experiment in class abvout resistance and temperature. The teacher told us to find out why light bulbs usually blow when you turn on the light. It must be related to the experiment we did which was seeing how resistance changed with temperature Homework...

Electric field inside the bulb! There are 6.3e28 mobile electrons per cubic meter in tungsten. The cross-sectional area of the tungsten filament in bulb B1 is 0.01 mm2 (1 mm2 = 1e-6 m^2). The electron mobility in hot tungsten is 1.2e-4 (m/s)/(N/C). Calculate the magnitude of the electric field...

Homework Statement circuit diagram showing what has been identified as an NPN transistor with the collector and base connected to neg and emitter conected to pos. The base is also switched by a photodiode and the emitter is supplying a light bulb.Question asks when will the light come on.Can...

Homework Statement First of all I apologise if this is in the wrong place. Anyway we have been given the task of finding out the efficiency of a solar panel, where energy from a light bulb is used to heat the water in the panel. I was just wondering if someone would just check that my...

Does it have an aura, or is the aura just a refraction defect of air?

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 An electric bulb is marked 120 V, 40 W. (a) Calculate the current in this bulb when operating on a 120 V supply. (b) Describe 3 different ways in which energy can be transferred from the filament when it is operating normally. (c) If the light bulb is now connected to...

What is the function of the synaptic end bulb on a motor neuron? Thanks!

Hey... After recently doing a practical in an English A2 Physics lesson, my lab partner and I noticed various odd results happening. The basic setup was a mains joulemeter (set to flash every 100j) in series with a bulb holder/socket type thingy... Next to it, a GLX Explorer (an electronic...

Homework Statement What is the approximate electric field strength of the electromagnetic waves radiated by a 100-W light bulb, measured 3.0m from the bulb? Homework Equations $$\vec{E}=\frac{kq}{d^{2}}$$ $$P=\frac{2kq^{2}a^{2}}{3c^{3}}$$ The Attempt at a Solution I solved for...

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...

Bulb with volume of 5 liters is filled with nitrogen n = 3 molls. The bulb is set in space, the bulb cracks and the gas starts to expand. The nitrogen is considered as a real gas. Find the change in temperature. Joseph van der Waals' constant equals 0.137.

Homework Statement the tungsten filament of a light bulb has a resistance of .07 ohm. if the filament is 27 cm long, what is the diameter Homework Equations R= p(L/A) Area of a circular cross section = (PiD^2/4) The Attempt at a Solution R= p(L/A) A= (pL)/r...

As we know the incandescent bulbs emit mostly heat and very small amount of visible light.Is there any way to increase the proportion of the visible light? If there is why is it not employed? Can anyone help me to start with it?

I say urgent because of the horribly small lecture I received on this section, a whole 3 minutes or so of examples. While I won't give further context I can say without a doubt I am completely lost. Here is the problem I am stuck on. In a string of 12 Christmas tree light bulbs, 3 are...

Hey... This is for a school projecct ... Well... look i need to lighg up a little light bulb(like a christmass, those little ones) but i don't don't know how, i can't use any plugs in the wall or anything... i was thinking on using some batteries and wires but i still don't know how... If...

Hey... This is for a school projecct but i feel like its best fiting here... Well... look i need to lighg up a little light bulb(like a christmass, those little ones) but i don't don't know how, i can't use any plugs in the wall or anything... i was thinking on using some batteries and wires...

Why does passing current through Wolfram filament, heats the Wolfram filament in light bulb? What happens with the electrons?

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...

I have a question. How does the size of the bulb (mercury) affect the range of the thermometer? I know that to increase the range, the bore size of the capillary tube should be large. Would the size of the bulb affect the range? If bulb is large - then there will be more mercury - so...

The following diagram is of a setup consisting of A bulb A pair of wires...making an angle theta with the place the bulb lies in now if the setup is seen by an observer moving at a speed 'v' relative the angle the wires make with the plane changes to phi>theta(i can provide the...

ok, I know I always think my questions are going to be dumb, but this time I should really get some credit for how dumb it is. but I can't find the answer on the internet so here goes: This little lamp I have says "max 25W," does this mean that the maximum output of the lamp is 25W, so a...

Homework Statement a flashlight bulb is connected across a 3.0-V difference in potential. The current through the lamp is 1.5 A. a. what is the power rating of the lamp? b. how much electric energy does the lamp convert in 11 minutes? Homework Equations P=I*V The Attempt at a...

Preserving the lifetime of a bulb ? My father claims that is is better do leave a light bulb on rather than switch it on or off when used often because he says, "Electric charges are very fast and damages the filament inside with each flick of the switch closing the circuit, even more damage...

Why can't you dim a fluorescent bulb?

Homework Statement The resistance of the tungsten filament in a light bulb changes with temperature according to equation (1), below. I am supposed to calculate the temperature of the light bulb at voltage 0.8280 volts and a current of 0.0853 amps. The bulb is connected to a 1.5915 volt...

Homework Statement The problem is that I cannot figure out why a filament will burn out in a particular spot. Higher resistance = lower current why does the filament heat up more? Homework Equations R2= R1[1+a(T2-T1)] Resistance = (resistivity * L)/ A R= V/I The Attempt at a...

Homework Statement You stand 2.7 m from a 150 W light bulb that converts 5% of the electrical energy dissipated within it to light. (a) If the pupil of your eye is 5 mm in diameter, how much energy enters you eye per second? ___J Homework Equations Iave= Pave/Area The Attempt...

In general, does more current/less resistence mean the brighter of the light bulb? How does voltage take into account in this case

What is a "vapor bulb thermometer"? The problem statement vapor bulb thermometer I'm simply looking for a definition. I haven't been able to find it on the internet. Before looking in a library, I was wondering if anyone knows which book to look for, or where on the internet a definition...

My hair is so curly, and I hate it so much.:frown: I wouldn't mind if it was wavy but it's curls a like 1cm length. And when dry it's especially hideous. I did a little research and found out that in curly hair the hair bulb inside the scalp is hook shaped, and in straight hair it's straight...

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