Wire Definition and 1000 Threads

Circulation of a magnetic field = closed loop integral ∫c B ⋅dl = μ0I B is mag field strength, dl is small line element, I is current Im imagining both B and dl point in the same direction from the diagram. So the dot product here, I picture as cosθ = cos0 Is that correct way to...

Speaking just of long straight wires, not loops, coils or solenoids. Ideal wires have no resistance. Of course they would have no capacitance. And real wires have some very small amount of inductance, no? Firstly, would an ideal wire have some ideal nonzero inductance? Why/why not? After all...

Hi everyone, I read somewhere that when a coil is wound on a magnetic core it's electrical length becomes longer than it's physical length. I remember seeing this formula L=l * sqrt Ue Where L= Electrical length l=actual (physical) length Ue=Core permeability Does anyone know if this is...

Homework Statement Calculate the frequency of a bead with a mass of m vibrating on a parabolic track equals to y=Ax2 Homework Equations F=ma The Attempt at a Solution Looking at the bead at any point which isn't equilibrium, I have: 1. may =N-mgcosθ 2. max=mgsinθ I tried to look at a...

I plan on using a 1 ft long, 0.005" diameter platinum wire as part of an electrode. The wire will be bare but will be inside a hollow plastic tube that has an inner diameter of 0.08". It needs to be able to carry a maximum of 1 mA for a length of 10 minutes, while not exceeding 60oC. I'm not...

Homework Statement The terminals of a 0.70 Vwatch battery are connected by a 70.0-m-long gold wire with a diameter of 0.100 mm. What is the current in the wire? Homework Equations V = IR R = pL/a The Attempt at a Solution I try to find resistance first, resistivity of gold is 2.2 * 10 ^-8...

ok so I was creating a connection today and used a 5 v led on a 1.5 v battery. Battery was in a case from radioshack and had insulated leads, full of twisted micro wire. Since there was no way to crimp it or strip the wire without me ruining the twists, I just bundled it to some non twisted wire...

Hi, I'm trying to calculate the length of wire that I need to wound a coil using a spool and wire of known dimensions. I was trying to use this converter but I'm not getting good results: http://www.had2know.com/technology/solenoid-coil-wire-calculator.html For instance: with a wire radius of...

Homework Statement A long, straight wire, radius R, carries total current I. The current is distributed in the wire so that the current density is proportional to s, the distance from the center of the wire. (a) Write an expression for the current density J in the wire, as a function of s...

Hello this is my first question here :) So here is my problem: We have a circle radius 50 (m), made out of iron wire mass 5.506206591207348477884587 Kg per meter of rope. Rope diameter 11/8 inces or 3.4925cm The wire rotates with 3 rpm in zero gravity 1)How can i calculate the tension? Thx...

A coil 3.65 cm radius, containing 560 turns, is placed in a uniform magnetic field that varies with time according to B=( 1.20×10^−2 T/s)t+( 3.05×10^−5 T/s4)t^4. The coil is connected to a 600-Ω resistor, and its plane is perpendicular to the magnetic field. You can ignore the resistance of the...

Homework Statement A straight wire carrying current I goes down the positive y-axis ( I is also in this direction) from infinite y to the origin. At the origin it changes direction 90 degrees and goes along positive x to infinity. Find B at (0,0,z). I'm given that ##\int_{0}^{\infty}...

Hello there! I have here a servo motor - Japan Servo AS27278 but don't have any idea about it. I make some researches on uncle Google about this model or kind of motor and fortunately I was redirected in here. Hoping somebody out here on this site knows and have knowledge about this kind and...

I have very little knowledge when it comes to physics. I'm trying to heat up a guitar string using electricity. The power source is 5 amps and only slightly heats up the string. I need a wire to get hot enough to cut through styrofoam. Please help with wire and power source suggestions.

Homework Statement An electric current is uniformly distributed throughout a long, straight wire that has a diameter of 0.05m. If the current through the wire is 6.0A, calculate the magnitude of the magnetic field: a). 0.02m radially away from the wire center b). 0.05m radially away from the...

Homework Statement The electron enters a straight pipe of circular cross section (radius r). The tube is bent at a radius R≫r by the angle α and then is aligned back again. Find the probability that the electron will jump out Homework Equations Tunneling probability in WKB approximation. The...

Homework Statement A long straight wire carrying a constant current I1 and a circular wire loop carrying a constant current I2 lie in a plane. The radius of the loop is R, and its center is located at distance D from the straight wire. What is the magnetic force exerted on the loop by the...

Homework Statement An infinitely long wire carrying a 1 A current in the positive x direction is placed along the x-axis in the vicinity of a 5-turn circular loop located in the x-y plane as shown in the figure. If the magnetic field at the center of the loop is 0, what is the direction and...

So here's my problem. For the past few years i have built a very large christmas tree in my front yard. 1200 lights or so... looks awesome it is 6m high, a 2m ring at the bottom and is a constant cone shape to the top point. To install the lights i start from the bottom and progress to the top...

I found this formula to approximate the inductance of a coil of wire. But what if a solenoid were composed of N separate loops, where each loop of the solenoid is connected to its own battery? That is, what if the solenoid had the same number of loops and the same geometry, except that each loop...

I just want to know if my method is correct in answer a question like this... Three impedances z1=(2-j5), z2=(3+j4) and z3=(8+j0) are connected in delta to a 3 phase, 400v 50Hz supply. 1. Find the three line currents Ia, Ib and Ic 2. Find the S,P and Q and power factor for the load 3. If the...

Hi Everyone, I could do some advice on wiring up a Piezo touch sensitive switch. I'm in the middle of building a desk PC project and thought it would be a nice touch to have a touch sensitive power switch, so I've bought a nice shiny touch sensitive illuminated Piezo switch and can't figure out...

Homework Statement Homework EquationsThe Attempt at a Solution This is how I drew it (in pencil) , but there should be a rheostat connected in series with the power supply, why?i can already calculate the resistance straight away by V/I

Okay guys I have an hour and thirty minutes before my exam; I know how to do the top problem; just use the formula B = mew x current/(2 x pi x r) then add the magnetic fields and use the right-hand rule to get direction, but I'm stuck on the bottom one.

In short circuit it is said that there is no resistance. So the current produce heat and wire is burnt. But as the rise in temperature increase the resistance then in short circuit heat must rise the resistance. How can we say there is no resistance in short circuit?

Homework Statement This is not entirely a homework question but more a question about a homework assignment. We were asked to find out why a filament of a bulb heats up by talking about microscopic ideas. This is a link to a website that contains the relevant information under the heading...

Hello all. I want to do some experiment but I thought I would go over this theoretically before trying out and now I have a doubt. Homework Statement I have a driver which produces say 600mA. I connect the driver to one end of Nichrome Wire. And the other end of Nichrome wire is in contact...

In https://in.answers.yahoo.com/question/index?qid=20120918081153AARHhnA, It says that "1.When the length of the wire is doubled,its volume remains constant, " How come ? Volume is Area times the length.. How come it remains constant if the length of wire is doubled ??

Homework Statement [/B] A sign with a mass of 27 kg is hanging in two wires both making an angle of 25 degrees with the vertical. Find the tension in one of the wires. Give your answer in Newtons (N) and with 3 significant figures. Homework Equations Ftens=gravity/sin(x) ? The Attempt at a...

Homework Statement A positively charged wire is bent into a semicircle of radius R, as shown in the figure below. The total charge on the semicircle is Q . However, the charge per unit length along the semicircle is non-uniform and given by λ=λocos(θ) What is the relationship between λo, R...

I have an electrical drawing which specifies a wired connection as 3# 10+ 3# 12v- Teck symmetrical. What do all these numbers mean?

I am doing homework for my Intermediate Electricity & Magnetism class. We are currently working on Electric Potential. There are a few problems I have attempted but I have gotten stuck on. I think I keep getting stuck when I have to find what |r-r'| is for uniformly charged objects to some point...

Aloha, I'm new here and stumbled across this site in my attempt to salvage a whirlpool washer motor to repurpose as a motor to grind barley to make my beer. Until now, I just used a hand crank and decided it's time to modernize. I just salvaged a nice looking, 3 speed, 1/2 hp motor from a...

A recent thread of mine eventually evolved into this question, but did not start off that way. I think the initial post was poorly worded and didn't ask the same question that the thread eventually became about, so I figured I'd post a new thread to directly address it. First let me start by...

Homework Statement 1. Two solid metal spheres are very far apart: sphere A (radius 44.1 cm) is charged to potential +2,346 Volts; sphere B (radius 63.6 cm) is charged to potential +8,848. Now, a long conducting wire connects the two spheres. When the charge has stopped moving, find the new...

About Electric field due to an infinitely long straight uniformly charged wire my book says the assumption that the wire is infinitely long is very important because without this we can not take vector E to be perpendicular to the curved part of the cylindrical gaussian surface.I think it should...

Homework Statement A copper wire has a diameter of 204.3 mil (1 mil = 0.001 in) and a resistance per unit length of 8.31x10^-4 ohm/m. The wire is coated with plastic insulation with thermal conductivity k = 0.20 W/(m K). The upper temperature limit of the plastic is 400 K. The air surrounding...

I have a DC source. then I connect a capacitor from the +ve to ground. if all connection are made from ordinary , copper for example, wires then electrons flow from negative to positive terminals.So electrons from the negative side of the capacitor would flow to the positive. I wonder what...

After solving this problem I ended up with--(2a is the length of the wire)(integral limit is from -a to +a) (x is the ⊥ distance from centre of the wire to a point P where we have to find the net field ) E[SUBx]= (1/4Πε)*(Q/2a)∫x.dy/(x^2+y^2)^3/2 P.S- sorry, I'm not able to upload the image of...

'The ends A and B of a potentiometer wire are connected a driving circuit consisting of a strong battery, a plug key and a rheostat. The driving circuit sends a constant current i through the wire AB.' Can anybody please explain me as clearly as possible what is meant by driving circuit and...

Need a little assistance, and yes I should know how to answer this but... The project is from an Oil and Gas system. Deadline anchor and load cell. a reel has wire rope on it that acts on an arm that puts pressure on a load cell. I'm trying to back calculate the force in lbs on the wire rope...

Hi! I have performed an experiment measure force on a wire with electric current in a magnetic field. I got 3 graphs: Force as function of length (L) of wire, Force as function of current (I) and Force as function of magnetic field (B). In all cases, I got approximately a straight line through...

Is magnetic field due to straight wire on the line of the wire itself zero? If yes, give mathematical proof.

I am creating a horizontal zip line, in which a rider will be pulled with a rocket engine. Completely serious. One end of the wire will be secured to a tractor and the other to a large tree. The zip line will be made from 12.5 gauge (2 mm) galvanized class 3 200 KPSI minimum tensile strength...

This thread is continuation to: https://www.physicsforums.com/threads/self-inductance-of-a-straight-current-carrying-wire.461622/ It's a really old thread, but I happened to come across the same problem a while back and since the old thread does not give the correct answer, I decided to create...

Homework Statement Hello. The resistance of a wire increases when the temperature increases. How would this cause the shape of the graph to change? Explain why. The graph shown is a straight line graph with the line traveling at 45 degrees path. The x-axis is VOLTS. The y-axis is CURRENT...

Homework Statement The bead of mass m starts to slide without friction from point A. the mass of the cart and the rail is M. What is the max displacement of the wagon during the motion of the bead? What is the force the rail exerts on the cart when the cart's velocity is maximum? What is the...

Suppose that a ferrite bead is put around a cable where a constant current I flows, just like in this image. The coordinate system has the z axis along the cable. Let's evaluate the current through the (x,y) plane: according to the Ampère's law, the only magnetic field component generated by...

Homework Statement With respect to a frame of reference K, a conducting wire of infinite length and internal radius "a" carries a current I -due to a flow of electrons- and has no charge density. An observer in a reference frame K' is moving parallely with respect to the wire. From the...

Homework Statement A 45-m long wire is coiled so that it makes a coil containing 100 circular loops, one on top of the other. If the wire carries a current of 13 A, what is the magnetic dipole moment of the coil? 21 A·m2 6.7 A·m2 3.3 A·m2 2.6 A·m2 1.2 A·m2 Homework Equations B(z) = u0/2pi...