What is Bulb: Definition and 283 Discussions

In botany, a bulb is structurally a short stem with fleshy leaves or leaf bases that function as food storage organs during dormancy. (In gardening, plants with other kinds of storage organ are also called "ornamental bulbous plants" or just "bulbs".)

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  1. L

    Current flowing in an open circuit

    1. Consider this diagram. Does the bulb light up? The equation I=V/R tells me no, but if there is a potential difference between the two points, surely current will flow and the bulb will light? As there is nowhere for the electrons to go, I assume it will only light for a very short period of...
  2. O

    Misc. Let's change another light bulb

    You've helped me change a couple bulbs so far, hopefully this is the last one. There's a recessed light on a hinge (a gimbal light maybe?) There are three exterior white rings - the outermost is a trim, the middle is a flat piece, the inner is ridged. Both the middle and inner piece move on...
  3. NTL2009

    Can RGB LED simulate incandescent bulb 'glow'?

    Maybe more of an optics/biology question than electrical, but... My wife wanted some lighting on a cabinet nick-knack shelf. I thought it would be fun/interesting to use a strip of RGB LEDs and a controller to adjust the light color to whatever we wanted, plus the LEDs would be less heat and...
  4. J

    I Minimum light bulb wattage for solar simulator

    I am trying to design a simple homemade PV solar simulator. I have picked metal-halide lamps as my light source. If the PV panel has an area of 1m^2 and I wanted to achieve spatial uniformity across the irradiated surface with an irradiance of 1000 W/m^2, how do I go about selecting what...
  5. A

    What is this type of bulb or lamp?

    Hi there! I have few years still without any solution. I could find just only one exemplary of this bulb or lamp there I share pictures, this is exactly what I need to know what it is, brand or datasheet. The base is E27. AND the most important, In this VIDEO you can see the lamp...
  6. K

    Frequently switching a lamp ON and OFF in short time reduced bulb life?

    I had a lamp that was good for 10 years but two years ago it was burnt out, I replaced it and in this two years we have a naughty kid playing with it, it is burnt out recently again. Is it likely due to his behavior (switch it ON and OFF within short time) or quality of light bulb in recent...
  7. Dario56

    I Energy Flow From Battery to the Light Bulb

    When we connect tungsten filament light bulb to the battery, filament becomes hot due to electrons losing kinetic energy in the electric field inside of conductor. Heat is eventually converted to electromagnetic radiation making light bulb shine. Light energy comes from flow of electrons and...
  8. O

    Misc. How do I change a really high light bulb?

    Your guys really helped me out with my last bulb problem so I thought I'd try again. There's a bulb over a staircase that is - a recessed floodlight - about 18 feet above the stairs directly beneath it (it's over the bottom of the stairs, and the staircase is exposed to the next floor) About...
  9. M

    Can a Resistor Simulate a Light Bulb Load for LED Bulb Installation?

    Hello All, I have a snowmobile that uses a shunt type regulator to control voltage. They require a constant load (headlights) to work proper. The 2 stock bulbs are 55 watts on low with the system running 12v. Racers install another set of hand warmers, wired to high, and tape them to the...
  10. T

    Why doesn't a light bulb draw 100 amps?

    I am asking this question in behalf of my father ( who does not have an account here to ask this question himself). My father said he does not understand why a simple light bulb in an AC circuit does not draw far more amps than a simple light bulb draws. He thinks that a typical light bulb...
  11. I

    Good LED bulb will not work in a socket

    Hi all, 25 year electrician here with a strange (to me) issue. I have a science project lamp that has a dimmer, a volt meter and a socket with a bulb in it. The kids can turn on the bulb, rotate the dimmer and watch the voltage go up and down on the meter. Simple enough. Every dimmable bulb...
  12. S

    Is it possible to build a laser from a light bulb?

    In my drawing you can see: A generic bulb covered by a mirrored hollow ball. The hollow ball has a small hole (1 mm diameter). So the complete light will go through this small hole. The lens will bundle the light in a very distant (100 km) focal point. I guess it might be hard to create such a...
  13. Greg Bernhardt

    Anyone have a light bulb blow up?

    Was shaving just now and one of my mirror wall light bulbs blew up. Luckily it's encased in the light fixture with an opening at the top so it was contained a bit, but some glass blew up through the top and rained on me. The glass was very hot, so I'm guess it wasn't LED.
  14. C

    Voltage received by each bulb in a circuit

    Summary: Voltage received by each bulb in a circuit How much Voltage does each bulb receive in the diagram below? (In terms of 1v being the voltage supplied by each cell)
  15. Baibhab Bose

    Temperature of a thin bulb filament

    In my assignment question, the length L and radius r is given and asked to find out how the Temperature of a thin bulb filament which depends on those two parameters. and the answer is r^(1/4)*L^(-1/2). I can't figure out how. Which relation is involved?
  16. O

    Comparing the brightness of each bulb in a circuit

    Homework Statement Four identical light bulbs are connected to a battery as shown in the diagram. Switch S is originally closed. If switch S is opened, what happens to the brightness of each bulb? Homework Equations V=IR The Attempt at a Solution - By opening the switch, no more current...
  17. Shivang kohlii

    Engineering An electric bulb of 500 W at 100v is used in a circuit

    If the circuit has 200 V supply. The resistance R that must be put in series with bulb so that it draws 500 w is? 2. Relevent equations P= v^2/r I = v/r 3. My attempt at the solution R= V^2/P r (bulb)= 10000/500 = 20 ohm Now for 200 v supply .. P= 500 W V= 200V Rnet = 20 + R R+20= 80 R= 60...
  18. Jesse44

    Danger of touching a broken fluorescent bulb?

    I was disposing of some old CFLs at IKEA this morning. They have a few bins there for safe disposals. I am already insanely paranoid of breaking CFLs in the first place, so I took great caution placing mine gently into the bins. I spent a few minutes making the pile secure so they wouldn't fall...
  19. N

    Which bulb will glow brighter in a series and parallel circuit?

    1. The problem, statement, all variables and given/known data Say there are 3 bulbs of power 100W, 500W and 1000W connected in series. Which bulb will glow brighter and why? How would it be different for a parallel combination of these bulbs? Homework Equations P=I^2R P=V^2/RI think in series...
  20. J

    LR circuit - Which bulb gets dim quickly?

    Homework Statement Homework EquationsThe Attempt at a Solution When the switch is off , the current in the inductor doesn't drop to zero instantaneously . The current in the loop consisting of inductor , resistor and two bulbs will decay gradually . Now since there is a complete circuit...
  21. J

    Which way do I measure the potential difference

    Homework Statement All the bulbs in the circuits are identical, as are all the batteries. Rank the magnitude of the potential difference between points M and N. Homework Equations V=IR The Attempt at a Solution My most fundamental question is actually which way do I know to take the...
  22. P

    How many batteries does it take to light this bulb up?

    Hey guys So lately, I've been interested in circuits. I am good at maths, but my physics isn't as good (hence why i signed up to ask questions). So I have a question. Imagine you have a simple circuit, like below: Simple circuit, 1 bulb and X amount of batteries. So my question is, how many...
  23. H

    How to find the power consumed by the light bulb

    Homework Statement (Is the image read-able now? ) The fig 1 shows the relationship between voltage and current when voltage is applied to a certain light bulb. Next, in fig 2, the bulb is connected in series with a 12-V battery and a 5 ohm resistor. Question : what is the amount of power...
  24. A

    100 W and 60W bulb plugged in separately....Which with more resistance?

    Homework Statement If you have a 100 W bulb and a 60 W bulb connected to separate electrical outlets, which will be brighter? Which has more resistance? Explain. 2. Necessary formulas P=IV and (maybe?) I=V/R 3. The Attempt at a Solution I know for sure the 100 W bulb is brighter. However...
  25. ephphatha16

    Resistance of a tungsten filament bulb at 20 C

    I was looking for any credible sources who could reveal the resistance of a normal tungsten filament bulb at room temp 20 C? I heard its cold resistance is about 9.5ohms. Is that the resistance at rtp? Thanks a lot in advance!
  26. J

    Could this bulb resistance problem be modified ?

    Homework Statement Homework EquationsThe Attempt at a Solution The original question given above has been correctly answered by me .The correct option is 2) . Thinking more about this problem made me wonder if there could be a combination of L1,L2,L3(different from that given in the...
  27. zdcyclops

    B If the moon were a light bulb how many watts would it be.

    If the moon were a light bulb how many watts would it be.
  28. M

    Light Bulb in a Box: Velocity Change After Release of Photon?

    Homework Statement [/B] A box is traveling with a certain velocity in space. Inside the box is a light bulb, which is capable of releasing one photon of light. The light bulb harnesses the energy from the box; it does not require an outside power source but instead uses the energy on the...
  29. J

    Probability that a bulb lasts for at least 7 months

    Homework Statement Homework Equations I don't even know how to start this. Should I use Poisson's distribution. Or assume f(x) = exp(-x) And then since mean is given we have integration from 0 to infinite xf(x) is mean. Not sure what this will give. The Attempt at a Solution Let f(x) be...
  30. D

    Bulb Turbine Head: Inlet, Outlet & Head Explained

    Hi All, My question is about bulb turbines and head. Bulb turbines are used for tidal energy. I guess the inlet and the outlet of the turbine (or the pipe where the turbine is mounted) are both under water. Is head the difference in height between the water surface at the inlet and the water...
  31. S

    How Can We Determine the Operational State of a Bulb Without Using an LDR?

    What methods other than Light Dependent Resistor incorporation are there to determine the 'bulb state'? I'm guessing it's going to include the use of another type of optoelectric component? Thanks
  32. M

    How to calculate pressure of a bulb in a system

    p1=Pa+(pgh) p2=p1+pgh Bulb A SG= 0.87 pressure = 200kn/m^2 Bulb B SG= 13.6
  33. Simon Clement

    Why Must an Incandescent Bulb Filament Have a Low Evaporation Rate?

    Hello here Why is it necessary that the filament of an Incandescent bulb to have low evaporation rate below melting point?
  34. B

    Current, voltage : brightness of bulb in parallel or series

    Hello I'm working through a book (with answers) but am struggling with voltage, current, resistance and circuits. Please check my understanding below and let me know if I've finally understood. Thank you. In particular I'm confused in Q2 Q1. A student connects light bulbs, A and B, and...
  35. T

    Probability of bulb malfunction

    Homework Statement consider 8 packs of bulb and let x be the number of bulbs in a pack that 'fail' the first time they are used . If 0.02 of all bulbs of this type fail on their first use and each 8-pack is consider random sample , what is the probability that anyone 8-pack has no bulb fail on...
  36. C

    Electric circuits -- Finding the V-I characteristics of a light bulb

    Homework Statement Homework EquationsThe Attempt at a Solution I know Ammeter and bulb goes in series and Voltmeters in parallel. But am I supposed to connect the voltmeter to the little arrow on the potential divider, or just across the bulb?
  37. Manolis

    Driving a neon bulb with high frequency

    I want to produce a 100 volt peak to peak symmetrical AC waveform to light a miniature neon bulb. It strikes at about 90 volts then settles ("clamps") at about 50 volts, according to the spec. I want the frequency to be at least 10 kHz for easy filtering because the circuit will also be passing...
  38. dholbach

    Can a cathode ray tube be made from a light bulb?

    Light bulbs and cathode ray tubes are structurally similar in some respects. For example, both contain a filament -- in the light bulb, the filament heats up to produce light, while in a cathode ray tube, the filament emits electrons, which are then steered into a target (in a CRT TV, the...
  39. jlmccart03

    EM Waves - Would the bulb glow?

    Homework Statement A long, thin steel wire is cut in half, and each half is connected to a different terminal of a light bulb. An electromagnetic plane wave with E and B moves past the wire as shown. Part B: Suppose the wire were oriented parallel to the y-axis, as shown above. WOuld the bulb...
  40. A

    Why does this bulb get brighter after the switch is closed

    Homework Statement Homework Equations None The Attempt at a Solution The answer is B, bulb B will be brighter than before. My thought was that initially, the current gets split so that 2/3 I0 goes to the branch with 2 bulbs, since it has twice the resistance of the first branch, and that...
  41. N

    Checking the voltage in a light bulb socket

    Hello, I was trying to check with a voltage tester if there was voltage in a light bulb socket (Edison type, no bulb present). Explosion happened (a relatively loud sound) and the safety circuit switch turned off. My question is, how can one explain this with the laws of physics and how can...
  42. V

    Uncovering the Source of Extra 267 J in Standard Incandescent Light Bulb

    Ok, according to my in depth research, wiki, the filament of standard incandescent light bulb will reach a temperature of roughly 2500 K. According to Stefan-Boltzmann, the power radiated from an object at temperature T (K) is given by P= A ε σ T^4 . Suppose the filament has a radius of 1mm...
  43. Alvaro8

    Help with light bulb radiation

    Hi guys I´m doing an experiment in thermocouples electricity generation by thermal radiation of Sun (As an addition to Solar panels). I´m still in high school and I don´t know a lot about the topic. I would like to simulate sun thermal radiation with a 100w incandescent light bulb as an...
  44. A

    Removing a Light Bulb: How Does it Affect Resistance and Current in a Circuit?

    Homework Statement Homework Equations Ohm's Law, Equations for parallel and series combinations of resistors[/B] The Attempt at a Solution Working this problem I obtain a solution that doesn't make sense, which is that the bulbs are dimmer. If I assign 10 ohms to each bulb, I believe...
  45. A

    Inductor and bulb in an circuit

    Homework Statement the problem statement is provided in the attached file Homework Equations logic based , basic principle of inductors. The Attempt at a Solution after switch is opened the more the current passes through the bulb , more will be the brightness . earlier in the steady state ...
  46. J

    12 Volt 100 Watt Bulb V 120 Volt Bulb 100 Watt

    Does a 12v bulb rated 100 watt give the same amount of light as a 120v bulb rated 100 watt?
  47. PhysicsNewbie321

    Why wouldn't the bulb light up in this circuit diagram?

    Why is this wrong? Does the (v) need to be on the right side? Is this right? Voltage symbol V is measured in |_____ joules (J)| <-- Voltage is a measure of the amount ______<--- volts| done on a unit _____<---?
  48. S

    Pressure Drop In Bulb : Application of Graham's Law

    Homework Statement The pressure in a bulb dropped from 2000 to 1500 mm of mercury in 50 minutes when the contained oxygen leaked through a small hole. The bulb was then evacuated. A mixture of oxygen and another gas of molecular weight 72 in the molar ratio of 1 : 1 at a total pressure of 6000...