Lamp Definition and 179 Threads

I am very bad at electrical applications. I would like to install 2 separate switches that can turn on and off a lamp. They are connected but located at 2 places. When one is switched on to turn on light, the other can also be used to turn it off later and vice versa. This is an extremely common...

Dear PF Forum, I have a question again about Doppler effect in relativity. Before I ask about mirror and lamp, I want to refresh the discussion again as in my previous thread: https://www.physicsforums.com/threads/doppler-for-light.823942/ The formula for Doppler factor for light is. ##f =...

Hey everybody, I'm right now trying to solve a question I found in a German physics competition 2006 concerning the diameter of a thin camera lens. I'm not able to find a solution, since there is basically nothing given. Here the task (I underlined phrases which might be important): A ruler...

Hi everyone, searching on the web about how the fluorescent lamps work, I cannot understand if the UV is emitted by the noble gas or the mercury. For what I understand, both of them ionize, and the UV light is emitted after the collision of the electrons with the atoms, but I would like to...

Hi everyone, So one of my students has asked me a question which I'm not sure how to answer. The question is: Why does the wire that supplies current to the filament lamp in a light bulb not heat up, even though the filament itself does? Please let me know your thoughts! Thank you :)

A 60W lamp and a 120W lamp each have a potential difference of 120V across their terminals. a) What is the current through each lamp? I think you use the formula I = P/V and so: Lamp #1 = I = 60/120 and Lamp #2 = I = 120/120 But I don't know if that is right? Thank you so much for the help!

Hi all. We're currently working on a project and need to know the irradiance hitting a steel sheet some distance away from a halogen lamp. The setup looks like: The problem is we can only measure the lux at the surface of the steel sheet, and I believe in order to convert lux to irradiance...

Hey, we are trying to couple the light of a 75 W Xe Arc Lamp (Hamamatsu L2194) into a 800um(0,8mm) diameter fiber bundle (7 fibers). Now we have 2 plano convex lenses (25mm diameter, 30mm EFL, edmund serial #45-364), the first for collimating the second for focusing onto the fiber. We are...

Homework Statement The weight of rod AB is 4[N] and that of piece D is 10[N]. the moment at joint C is 1.8[Nxm]. what is the weight of rod AC. Homework Equations Moments: ##M=F\cdot L## The Attempt at a Solution Rod AB doesn't contribute to the moment at C: $$10\cdot 15+180=W_AC\cdot...

Homework Statement A lamp is connected to the secondary part of an ideal transformer. What will happen to the brightness of the lamp if the number of turns in secondary coil is increased? Homework Equations Vs / Vp = Ns / Np = Ip / Is P = V.I = I2R = V2/R The Attempt at a Solution I have...

Hey there! Can somone please help me with this problem? The problem Translated from Swedish (sorry for possible grammatical errors): L(from Europe) travels on the Trans-Siberian railway from Moscow to Vladivostok. His lamp battery dies when he reaches Irkutsk. He buys a Russian battery and that...

So my dad got this Salt Crystal Lamp for a wedding gift that supposedly freshens the air naturally, and I need some help explaining to him why this doesn't actually work. It says on the box: "This lamp is scientifically proven to work like an air purifier. When lit, it can emit negative ions...

Homework Statement Cheese Board Pizza just hired me to design a radiant pizza warming system. The pizza must be maintained at 250 F until the order is picked up by the delivery driver. The one square foot pizza sits on a ½ inch thick ceramic pan (k = 0.50 BTU /hr ft F) on a counter that is at...

Today I was sitting at my desk where I volunteer and it was kind of slow so I started messing with my desk lamp. I wondered how fast light travels from the bulb to the desk surface, but I didn't know. What I want to know is about how fast does the light travel to hit the desk when the light...

Homework Statement Above the center of the street a lamp is hanged. A lamp radiates equally in all directions. How high does the lamp have to be so the edge of the road is as bright as possible? Homework Equations The Attempt at a Solution I'm kinda lost here...

Homework Statement The figure shows the circuit of a flashing lamp.There is a current through the lamp (see the photo) only when the potential difference across it reaches the breakdown voltage VL; the capacitance DIScharges completely through the lamp. (a)A lamp has breakdown voltage...

Homework Statement The potential divider XZ has a potential of 3.0 V across it. When the contact is at the position Y, the resistance of XY equals the resistance of YZ which equals 12Ω. The resistance of the lamp is 4.0Ω. Picture of the relevant circuit...

Hey PF. I received a Himalayan salt lamp for xmas, and it's suppose to add more negative ions to the air which is good because apparently pollution mess's up the balance. Does anyone know if these things actually work?

Fluorescent tube lamp (FTL), in very simple words, produces light from excitation of atoms due to bombardments of electrons. A compact fluorescent lamp (CFL) is a coiled-shaped version of FTL. http://upload.wikimedia.org/wikipedia/commons/3/31/06_Spiral_CFL_Bulb_2010-03-08_(white_back).jpg...

hello, I am new to this forum (so bear with me) I've got a lamp on the ceiling of my kitchen, its got a particular setup that Ill try to reproduce ceiling--------------------------------------------------------- -----------------hook------------------------hook--------...

Hello. What sort of commonly accessible material can block harmful UV from a 150W Xenon arc lamp, without blocking much of visible light? Lamp relative spectrum (a bit around 250nm, growing to a lot at 400nm): Enough UV should be blocked for the lamp to be usable as a regular...

(not exactly sure where I'm supposed to post this) i was looking at my UV lamp that i got from walmart. i was looking for a wavelength on there but i only saw "color temperature" i immediately thought Wien's law; so then i calculated the peak wavelength and got 96nm which is on the far side...

You have a yellow lamp in your spaceship. Now you accelerate your spaceship significantly. Then you stop accelerating. Does the lamp still have the same color? I would think it should, but I reckon differently as follows: Consider the situation from an outside observers point of view, resting...

I think i have looked at like 20-30 web pages, and i can't find a simple step-by-step explanation of the operational principle. I know, that when a rare gas like Helium, relaxes from an excited state two characteristic emission lines occur. But how do you excite the gas in the first place...

I had a lab with photoelectric effect and we measured different colors wavelength/frequency by finding stopping voltage vs current. Then we used no color filter and used the mercury vapor lamp and had to find the wavelength which was around 400nm. Questions were why was this wavelength the...

Homework Statement Two 640-candle lamps are placed 6.0 ft apart and 8.0 ft above a table. Calculate the illuminance on the table directly below one of the lamps. Homework Equations The illuminance equation, to the best of my knowledge is as follows: E = I/s^2 and E = (I/s^2)(cos x)...

Homework Statement The power supply for a large flash lamp is shown below where a 500 V DC power supply changes up at 10 μF capacitor that then discharged through the flash lamp. Such a system is potenitally lethal, so to reduce risk a bleed resistor Rb is connect across the capacitor to...

I just want to know the difference between fluorescent strip and compact fluorescent lamp... Thanks.

I was trying to study the inductor role in Flyback converters and all, they seem to rely on the principle that the inductor is first energized while the switch is closed and then, it acts as a voltage source itself when the switch is opened. All that is good, but I am confused with the...

I'm in the process of repairing a lamp that I found with a broken switch. I know the lamp mechanism is functioning because I've bypassed the switch and plugged it in and it works fine. I needed to buy a new switch and they all have a current rating. I'm using 1 60 W bulb with a standard North...

Homework Statement Hello. I have an exam soon so I need to do many exercises. I have a problem with one. I need to get an acceleration of electrons in lamp which energy is 14 000 eV and magnetic induction is B = 5.5*10^(-5) T. The Attempt at a Solution The correct result is...

Hi, I have a table lamp, ratings: 110 - 240V 50 - 60 Hz Max 60W The plug is fitted with 13A fuse. Now, the thing is, how did they calculate the max 60W out from these ratings? According to P = V * I, my max power should be a very large value. So can I fix a 100W bulb to this...

Homework Statement http://www.xtremepapers.com/papers/CIE/Cambridge%20International%20A%20and%20AS%20Level/Physics%20%289702%29/9702_s06_qp_2.pdf number 7aHomework Equations None reallyThe Attempt at a Solution The answer is that C is the faulty lamp because it short circuit. But how do I know...

Isn't the case that when the lamp filament melts the resistance of that part of the circuit goes to infinite? So why does the circuit breaker turn off current? Thank you Regards

Could you make a fluorescent lamp with krypton instead of neon or mercury? The wavelength doesn't really matter its just if its actually possible and if it is what pressures and voltages should be used.

I have a 100watt xenon lamp , the UV component comprises of 5-6% of the total spectrum emitted by the xenon lamp . How do I calculate at what power is the UV light emitted ? Is the whole spectrum being emitted at 100 W or is the power distributed through the spectrum? How is this...

Dear All I am trying to measure the spectrum of an incandesant 6V 15W tungsten microscope lamp. I have a reasonably old scanning monochromator (diffraction grating based) coupled to a fibre optic cable and it has given me the spectrum...

Homework Statement A lamp hangs vertically from a cord in a descending elevator that decelerates at 1.6 m/s2. (a) If the tension in the cord is 92 N, what is the lamp's mass? (b) What is the cord's tension when the elevator ascends with an upward acceleration of 1.6 m/s2? Homework...

Also the chemical involve in the W and iodine. Thx

Changing voltage - independent variable current flowing - independent variable The investigation was aimed at measuring current at different potential differences, before the filament lamp started to shine and when it was shining so as to observe both ohmic and non-ohmic behaviour. Also after...

Hi, I am currently doing a project to design a lamp and am really interested in using physics to gain a perfectly balanced design. I have come across this diagram... http://upload.wikimedia.org/wikipedia/en/a/a7/Lamp_2_counter_weight.PNG I just want to clarify a couple of things before I...

Hey there! I'm doing some experimental work at a microscope, where the lamp in use is stated to be "Lamp bulb: 12 V DC, 100 W halogen lamp bulb (Osram HLX 64623 or Phillips 7724)." I'm doing some calculations to analyse some of my images, and in there I need the intensity distribution of...

What can I do with a "CENCO High Pressure Mercury Arc Lamp"? I'm a high school physics teacher. I inherited a "CENCO High Pressure Mercury Arc Lamp." Are there any useful demos and/or labs I can use this for?

Just joined PF and my mind is completely shutting down on me. I need to design the base of a halogen desk lamp and am having a problem getting started. My biggest problem is finding the correct equation to use to begin calculating the numbers. It is a three dimensional problem. Can someone...

I have this neon indicator lamp that I would like to replace with an LED. It is a part of an old flash gun. The indicator is made to show "charge complete" and I've measured that to start from 240V and keep going until maybe 350V. The indicator lamp is connected in series with a 1.5Gohm...

hi guys Am a little week in physics.. so here is the situation: I have a disco light that uses a 12v 50w bulb to operate.. however it is too weak. Since at home i can change a 240v 50 w bulb to a 240v 100 w one... am just wondering if it is possible to change the 12v 50w to a 12v 100w...

Sorry for the stupid question, but what actually makes the lamp comes on, the tension applied to it, the eletric current that passes through it or the potency dissipated by it? I think its the current but I'm not sure and I don't know why? But if it were the current, what makes the lamp...

Homework Statement The outermost electron in a sodium atom can be in these energy states: (1)-0.82 aJ, (2) -0,48 aJ, (3) -0.31 aJ 1 aJ= 10^{-18} J. When we study the spectrum of a sodium lamp, we see a yellow line. Use the above given energy states to determine the wavelength of this yellow...

Hi, I am trying to collimate light from a mercury arc lamp. I know this question has been asked before here https://www.physicsforums.com/showthread.php?t=413437&highlight=collimation but it was first posted last year and since my situation is a bit different it didn't quite answer all of my...

I'm doing a story for our paper on this outdoor must be mercury or metal halide light that's been burning constantly at least since 1996. So says the owner who took over the property then. He says the photo switch isn't working so it never shuts down. And-there are two others nearby with good...