Wire Definition and 1000 Threads

Could someone please help. i need to connect a 12vdc motor which can draw 16 amps to a switch that has an led on it. the led is rated at 3v 20mA. The power supply i am using is rated to put out 12vdc at 30A I thought of the possibility of adding a resistor to the positive pole of the led. In...

so what I did wrong?

The work function of a metal is typically several eV. When we transmit electricity through cables of some 10-100kV, how come the electrons not having enough energy to escape from the metal?

Can anyone explain the above answer to me? What does the "change in area" mean?

Let us connect a battery of potential difference V to a wire. There is no resistance. Nothing! Now the battery creates some potential difference and the charges in the conducting wire move due to the Electric field created in the conductor by the battery. So, as the charge moves, its potential...

a) the EMF of ℰ induced on The Wire, as a function of the speed 𝑣of the wire you can find it. b) flow induced in the wire𝑖, 𝐶, 𝐵, and are denominated in 𝑙 𝑎 (𝑎= the acceleration of the wire). c) find the magnetic force acting on the wire in𝐶,𝐵, 𝑙 and𝑎. d) 𝑎 acceleration, 𝑚, 𝑔, 𝑙, and are...

In the given question they have not provided the dimensions of the coil so I assumed it to be very close to the wire and having negligible dimensions compared to the wire . Then EMF induced in the coil due to the current in the wire comes out as M*a . Which when divided by resistance gives...

When a magnetic field is moving (moving magnet) while a wire isn’t---in the reference frame of the wire, there’s no known magnetic force/effect on the wire before the introduction of motional emf and relativity. If viewed in the reference frame of the magnetic field instead where the wire is...

There’s a current i in the loop in the figure. The Ampere’s force iLB on a wire of length L exerts on charges in the wire but it does no work on the charges. The charges would go in circular motion if there were no wire. Then the wire exerts exactly iLB on those charges to keep the charges...

Here, the correct options are A,D. Solution: I got A as answer as ∫ B.dl=µI. But, the answer to the question says that it is a solenoid and therefore Bx=0 for point P. Here I'm a bit confused. I know this system resembles a solenoid in some ways, then By must have some finite value, but...

Summary:: Not sure if my solution to a magnetostatics problem is correct [Mentor Note -- thread moved from the technical forums, so no Homework Template is shown] I was trying to solve problem 2 from...

I think the right choice is c. I'll pass on my reasoning to you: We can think that if the formula of the potential is V(r)=\dfrac{kq}{r} If r tends to infinity, then V(r)=0. But the correct answer is d).

I am unsure how to go about this. I tried following the suggestion blindly and end up with with some cumbersome terms that are not the answer. From what I understand the derivative at each point would equal to T? Answer: I just can seem to get to this. I think I'm there but can't get it in...

Hello, in this problem I'm supposed to calculate de magnetic field due to a bent wire at any point of the x-axis after the bending of the wires. It is obvious that the part of the wire that is parallel to the x-axis makes no contribution to the field so we can focus on the other part of the...

I explained what I want to tell you in the picture I add. Thanks in advance.

I have a project for which I am looking for a black anodized wire. I feel I can find this in aluminum wire pretty easily, but if possible, I would like to use something that might be stiffer. Wikipedia says a variety of metals ca be anodized, but I don't recall ever seeing such products and...

I made this scenario where I am looking for the total current running through a wire (I_0). I am also trying to model the current running through the wire (I_0) considering the harmonics contributed by the four loads. But since Fourier stated that a complex waveform is the discrete sum of some...

No attempted solutions.

Hey everyone So this is question shown below I'm not so sure where to begin with this, but I thought I'd work out the net magnetic field first How would I work out the magnetic field strength that is acting on the vertical current-carrying wire. Since I do not know what d is in this case...

I'm setting up a Faraday/Lenz Law lab and was wondering if anyone had a suggestion on what gauge of wire I should use to get the best results. We don't have any wire here so I can't test it myself. Thanks.

Is there a way to broadcast emergency messages via cable radio? Its not really radio but audio going out from copper or fiber using existing landlines or CATV cables. No tuner needed, could just be a speaker. The system I am looking for does not need internet or mobile connections. I imagine it...

Consider the following experiment: from a lacquered copper wire we cut off twenty to thirty pieces of about 10 cm. From them we form a bundle of parallel wires and connect the two ends with one more wire each. The other ends of these two wires are connected to a sensitive analog ammeter. We hold...

Hi there! I have recently been given this question by my teacher as shown below I'm struggling to see the set up arrangement for this circuit This is what I have drawn so far How would I fit in the third wire here and ensure I have closed loop circuit so that current can begin to flow...

This is for an experiment to deflect a 28 SWG wire between two magnets, 3cm apart, by passing a current through it (example attached). The force on the wire is obviously F = BIL, but the wire will be passing at 1.5cm from each magnet so there will be some significant fall off of B and I can't...

I tried to solve the above i have one confusion here. I have marked the areas as shown B2 = B4 = 0; B1 , B5 Out of Page ; B3, B6 Into the Page. B1 and B5 Calculation Now main doubt is regarding the B field of the finite wire let us say 1. I took the derivation of the infinite wire as below from...

Assume that an infinite metallic plate A lies in the xy-plane, and another infinite metallic plate B is parallel to A and at height z = h. The potential of plate A is 0, and the potential of plate B is constant and equal to V. So, there is a uniform electrostatic field E between plates A and B...

For a infinitesimal wire of lengh dx, the induced potential difference in an uniform B field perpendicular to it's motion is : dE=B.Vp.dx, where Vp is the component of the velocity perpendicular to the wire. Looking to the big wire I tried to take an arbitrary point express dE in function of...

angular frequency= 50 rad/s= 2*pi*frequency frequency= 7.96 Hz k=2*pi/wavelength k=2*pi/(2*1.6m) = 1.96 velocity=angular frequency/ k velocity=50/ 1.96 = 25.5 m/s For some reason this velocity is wrong

In a closed circuit the battery sets up a potential difference which causes charge to flow. I understand potential difference as the measure of electric potential energy per unit charge, the amount of energy required to move a charge from one point to another per charge. for example when a...

Shouldn't the answer have the same magnitude regardless of sign convention?

Not a homework. Just self-studying electromagnetism. I am stuck at understanding the very beginning of the solution steps in this example: The E as given in the solution is the field away from a long straight line with charge Lambda. That's clearly not the current configuration. E should...

I think I have to assume a point like P in the semicircle. The point in terms of r and θ: P (r,θ). So the magnetic field at that point: B = µI/2π(R+rcosθ) . So the magnetic flux: Φ = ∫B.dA= µI/2π ∫∫ rdrdθ / R+rcosθ . Is this the correct solution?

Folks, I'm not sure if this is the correct forum topic for my question, but it seems to be close or related. Question: If you have a wire carrying current then it creates a magnetic field as in the diagram in the link below...

Mentor node: Added code tags From=menu('select:','c', 'g', 'a', 's:'); This is part of my code and I'm not coming up with anything close l=input('input wire length') %current copper=12.5572...

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I tried to think why Ampere's law seems to fail in this case. For me it was clear that there is no symmetry in the z direction, there is no translational symmetry because of the finiteness of the wire. On the other hand, I know that Ampere's law is independent of the loop we take. This also...

Hello, I've done some background research on this, and answers seem to vary. I would like to calculate the amount of heating in a wire. Let's say I want to heat a wire up to 60 degrees. I have 1 W of power and 150 mA of current at my disposal to do so. How could I estimate the wire diameter...

Not sure what to do here, but I do know that magnetic field is pointing in the paper according to the right hand grip from current carrying wire. Hence I can calculate magnetic field to be: ##B = \mu_{0} I/2\pi r=(4\pi * 10^{-7})(50)/2\pi (0.004) = 3.94784*10^{-7}T## Now from what I...

Dear All, Hope you are fine! Hope this is the right place for this question. If not, my apologies. We just replaced the complete wiring of our apartment with three wires (live, neutral and ground + new circuit breakers + residual current device). Last week I noticed some tickling on my fingers...

How to find the length of a wire of a 3000 Kelvin incandescent light bulb that produces L = 60W of power. The diameter of the wire is 0.00005m. I'm quite confused, as the resistivity of the bulb isn't given so I'm not sure what equation to use as resistivity = resistance × area / length does...

I can't for whatever reason figure out where the sin(theta) term is coming from in the attached picture of page 306 of Griffiths' 4th edition EM text. The paragraph says it comes from the dot product, but I just don't see where it's coming from.

Question: In Figure (a), a circular loop of wire is concentric with a solenoid and lies in a plane perpendicular to the solenoid's central axis.The loop has radius 6.13 cm. The solenoid has radius 2.07 cm, consists of 8230 turns/m, and has a current i_sol varying with time t as given in Figure...

Summary: Insulated copper wires (not plated) inexplicably turned into gray powder. Wires are intact between affected spots. This is a piece of common red/black loudspeaker cable, with PVC insulation, pulled from service after about 18 months from installation. It was used to feed a small...

I want to know the total energy contained in a magnetic field due to a long wire (just consider a 1m segment) as a 1amp current is turned on starting at time zero. I'm assuming zero turn-on time for convenience. At t=0 the cylindrical field is formed and I wish to know the total energy as a...

i've started from this I1=I2 then I1= JA1=##\frac {E l} R## I2= JA2=##\frac {E_2 l} R## but can't get anything useful relating them. Am i forgetting any other useful formula? I get as result E4

What i did is: ##R=\rho\frac{l}{\Sigma}=\rho\frac{l}{d_2^2\pi-d_1^2\pi}## The problem is that I don't have ##\rho##. Is there a way to find ##R## without knowing it? Many thanks.

This potato masher youtu.be/j5IXRT3uxbA?t=170 would be easier to use if the spring wire had a tear-drop shaped cross section, with the pointy edge facing downwards. But how much would it add to the cost and feasibility? Can standard machines be easily rejigged to make non-circular wire?

So far the best I've been able to come up with is to use ##\vec{B} = \mu_0 \vec{H}## which gives me i_c = H 2\pi r j_c = \frac{H 2\pi r}{\pi r^2} = \frac{2H}{r} \therefore B = \mu_0 \frac{r j_c}{2} I'm fairly confident this is just terrible math and physics on my behalf but I'm struggling to...

Hello, I have a conceptual question regarding Faraday's Law: emf = d/dt(Φ), where |Φ|=|B*A|. My question is does Faraday's Law take into account the distance between the solenoid producing the non-coulombic electrical field (Enc) and a wire circling the solenoid, which now have an emf due to the...

Hi! I would like to know how to exactly calculate required wire diameter? For example, here I found this calculator on internet: https://www.solar-wind.co.uk/CST.html . It takes acceptable loss, volts, amps, and cable length for arguments. It specifies Vdc. Would it be different formula with...