Lightbulb Definition and 70 Threads

http://img257.imageshack.us/img257/7161/physics.png I only have one more chance at this problem and I can't understand why it isn't 1. I assumed that power in = power out and power = current x voltage. If the voltage remains constant, wouldn't the current as well? "In the circuit shown...

there is a 1000 light bulbs in a room near each bulb there is a switch which turns the bulb near it on in a push of a button and turns it off in a second push of a button and turns it on again in the third push of a button. 1000 students come into the room the first student pushing every...

Homework Statement I am currently carrying out an investigation into all the factors that affect the resistance of a lightbulb. Firstly, I have done a graph to show voltage against resistance for a 24W Lightbulb to see if Watts affect resistance, however my friends and teacher all told me to...

very cool. i wonder if there's a catch: http://www.telegraph.co.uk/earth/earthnews/4375077/Scientists-invent-2-energy-saving-lightbulb-that-last-for-60-years.html

I have a plant in my living room that doesn't get much light, and so it doesn't do very well. I've always been told that light from normal lightbulbs doesn't help because it's not "natural" light. But then I started thinking. The filament glows from the current and I'm just wondering what makes...

Homework Statement "Provide a true explanation for what you see as you look at a lightbulb underwater" (See the attached Image) What you see: Out of water -> white opaque light bulb Underwater -> clear outside, opaque white inside Homework Equations N/A The Attempt at a...

You're in a room with three switches that open three lightbulbs in a separate room. You don't know which switch turns on which lightbulb. How do you find out which switch goes to which lightbulb by entering the other room only once? You don't have any help, you can't see the other room while you...

Homework Statement The corroded contacts in a lightbulb socket have 5.0 Ohms of resistance. How much actual power is dissipated by a 100 W (120 V) lightbulb screwed into this socket? Homework Equations P = V^2/R V = IR P = RI^2 The Attempt at a Solution I found the resistance of the lightbulb...

Homework Statement The corroded contacts in a lightbulb socket have 8 Ω total resistance.How much actual power is dissipated by a 126 W (115 V) lightbulb screwed into the socket? Homework Equations P = I*V I = E/R The Attempt at a Solution I = 115/8 = 14.375 I don't know how to...

[SOLVED] resistance of a lightbulb? hey dudes so I've a lightbulb that says 60w 230v so i figure it draws 60/230 amps so i figure its resistance is 60w/((60/230)^2), which gives me 882 ohms so i checked this light bulb with a multimeter and it reads 65 ohms! so i figure that at its...

Homework Statement Hi, I made a eletric generator by connecting 3 motors (R/C car motor) to a spinning wheel. Each motor can generate approx 3 volts, it can generate approx 7.5 volt when I connected them in series. When I connect a motor output (approx 3 volt) to a flashlight light...

Homework Statement 4 identical light bulbs are connected either in series (circuit 1) or parallel (circuit 2) to a constant voltage battery with negligible internal resistance as shown. http://img413.imageshack.us/img413/7250/seriesoz2.th.jpg...

Homework Statement A 3-way lightbulb can produce 50W, 100W or 150W at 120V. Such a bulb contains 2 filaments that can be connected to the 120V individually or in parallel. a) describe how the connections to the 2 filaments are made to give each of the 3 wattages b) What can be the...

Homework Statement You have a large supply of lightbulbs and a single battery. You start with one lightbulb connected to the battery and notice its brightness. You then add one lightbulb at a time, each new lightbulb being added in parallel to the previous lightbulbs. As the lightbulbs...

Homework Statement Consider the simple circuit shown below, in which a light bulb with resistance R and a capacitor with capacitance C are connected in series with a battery and an open switch. The capacitor has a large capacitance and is initially uncharged. The battery provides enough power...

This probability problem is for my calculus class... a) A type of lightbulb is labeled as having an average lifetime of 1000 hours. It's reasonable to model the probability of failure of these bulbs by an exponential density function with mean = 1000. Use this model to find the probability...

I'm reading SpaceTime Physics by John Wheeler (not for school) and came across a problem that doesn't have answer in the back so i want to see if i understood it properly. the problem goes like this: You have two parallel wires with a battery and lighbulb connecting one end. on top of the two...

what is the electric field 1m away from a 100 watt light bulb i know that the power of the light bulb 100 watt = volts x amps so if the light bulb is a standard 120 volts then the electric field would be V / r im not sure about this because i know the electric field radiating...

So i was checking out some lightbulbs a while back and i noticed they had these numbers on it. One type had the number... it was like 3100K and the other was 5500K or so. Are these the temperatures corrposponding to the blackbody radiation associated with those temperatures? I know there's 2...

Suppose the light bulb in Figure 22.4b is a 60.0-W bulb with a resistance of 240 W. The magnetic field has a magnitude of 0.40 T, and the length of the rod is 0.60 m. The only resistance in the circuit is that due to the bulb. Minimally, how long would the rails on which the moving rod slides...