Current Definition and 1000 Threads

Homework Statement The current in a wire varies with time according to the equation I(t) = 6.00 A + (4.80 A/s)t, where t is in seconds. How many coulombs of charge pass a cross section of the wire in the time period between t = 0.00 s and 3.00 s Homework Equations I=dq/dt The Attempt at a...

I work in a large electrical machine shop. We have a test that no one can explain to me. We energise a dc field frame (in this case 6 pole) with ac and record the current draw, then reverse the polarity of connection, energise and compare values. If a pole is reversed polarity then a difference...

Homework Statement In a lab that I did in Physics we calculated the magnetic field of a solenoid while constantly increasing the number of time the wire was wrapped around the electromagnet. After I obtained all the values, plotted it in a graph and found the line of best fit, the slope came...

Homework Statement Determine the voltage drop and current through each resistor. *This is just my sketch of the problem since I couldn't take a clear picture of it. Homework Equations Ohm's law V= IR Parallel total resistance Req=1/R1+1/R2+1/R3+... Series total resistance Req=R1+R2+R3+...

【Moved from general forum. Homework template is missing.】 By KCL, -ID2 + (-I2) = 0 0 = ID2 + I2 Q1: Do you think this equation is correct? (i assume it is correct because it came from my professor's notes) Q2: Which node do you think this equation is used for making this equation with...

Homework Statement Consider an Ocean Current flowing at 2.5 m/s. a) How much energy is contained in a cubical block of water 1m on the side. (The density of the water is about 1030kg/m^3.) b) If the flow is perpendicular to one of the cube faced, what is the rate at which current flow carries...

would be really grateful if someone could help throw some light on this - its probably really simple but I am typing myself up in loops! I have a piece of wire which is placed in an external AC magnetic field which is varying sinusoidally. The wire is folded to make two rings of radii r1 and r2...

i made a speaker from a cup, a coil of wire and a magnet. I hooked up both of the ends of the wire to a headphone jack and it works. Albeit very low sound, but it works. Can you point me in the direction of some equations that will show me the most influential factors on how to make it louder...

Hi, The Circuit I am referring to is a simple series circuit with the resistance of the wire is negligible. I am confused about the fact that if we increase the resistance of a resistor in a circuit, the PD across the component will also increase. From my understanding I thought increasing the...

Homework Statement Two circular coils of diameter 30.0 cm are parallel to each other and have their centers along the same line L but separated by 22.0 cm. When an experimenter views the coils along L, the coil closer to her carries a clockwise current of 2.50 A. Find the magnitude and sense...

Homework Statement A wire along the z-axis carries a current of 6.8 A in the +z direction. Find the magnitude and direction of the force exerted on a 6.1-cm long length of the wire by a uniform magnetic field with magnitude 0.36 T in the -x direction. Homework Equations F=I(LxB) The Attempt...

I read in a book that during normal working condition (balanced system) the current through a neutral conductor is zero i.e., Ia+Ib+Ic =0 where Ia, Ib, Ic are phase current of three different phases a, b, c. How is that possible? I mean if you look at mathematical result of the phases they are...

Hello everyone Im new on the forum and I just discovered what are sync machines... I have really basic question what I still cannot figure out.. I did some experiments with motor for different field currents and torques. In the result I measured armature currents and did V curves. But next...

Hello, I am building a small car that upon hitting a wall will go backwards, in other words reverse the current flow. I have all the components requiered (resistors 3k and 1k, wires, 6V battery, and an H-bridge, locking button) only thing I do not know is how to connect them all together. If...

Hi, I am building a charger for my bicycle front and tail light that uses dynamo to charge them while cycling. However, depending on my speed, current is fed differently to lights and they start to flicker. Therefore, I was wandering if there is a way to make a constant current source which...

Homework Statement Homework Equations / 3. The Attempt at a Solution Looking to solve mistakes to study from homework. Here's what I had so far[/B]

Hey, so I'm just wondering what are the formulas needed to calculate the temperature of a wire after x amount of time as an electrical current is passed through it. I know how to solve for it... I just forgot the formulas. Thanks

Homework Statement I am confused what to do but I have to find the current through the battery: Homework Equations V=IR The Attempt at a Solution I decided to find the equivalent resistance and do V/R = I using the 14V, but I believe my Req is wrong. What is throwing me off is the...

Would lightning work in space? I think it would but you wouldn't be able to see it? Let's say I have some sort of device that creates a lightning bolt, if I shot it at a watermelon in a vacuum or another target would it hit the target, or nothing happen because of the vacuum?

A work colleague of mine told me that if you have an AC voltage across a wire and the frequency is high enough, there would not be any current, because electrons don't have time to move from one atom from another. Is there any truth behind this?

Homework Statement [/B] Estimate the total harmonic distortion [THD] present in the current waveform using the formula: Homework Equations ##THD\left(I\right)=\frac{1}{I1}\sqrt{\sum_{n=2}^\max\left(In\right)^2}\times 100\%## The Attempt at a Solution I have attached a worksheet for this. The...

Hello, I'm wondering how you would go about drawing a Feynman diagram for a weak charged current scattering interaction of a positron and a proton. I have attached a diagram of what I have tried but it doesn't conserve lepton number (I think this is a problem, from what I gather...

Hello Experts, I am a physics newbie with big ideas. I have a question. I am thinking about how to produce a zero Resistance Current. We know we can do this using super-conductors in sub zero temperature, but maybe there's another way. My assumptions (which could be wrong): 1) Resistance in a...

Homework Statement A single-turn wire loop produces a magnetic field of 41.2 μT at its center, and 5.15 nT on its axis, at 20.0 cm from the loop center. Find loop raidus and current. Homework Equations F = qv x BThe Attempt at a Solution I tried to use the above equation, but could not figure...

I'm having trouble understanding circuits, particularly voltage. So my question is more of a conceptual dilemma. Please correct my definitions and relations if it is incorrect. Voltage is the energy provided per charge, and this energy is converted to KE once the circuit is closed, or in other...

Is there a possibility that none of the current interpretations of QM are right? Or is the current interpretations all that there will be on the table?

Homework Statement Homework Equations For a basic RC circuit during charging: q = CV(1-e-t/RC) i = V/R (e-t/RC) The Attempt at a Solution I can solve basic RC circuits but this is just out of my realm of understanding. I can also find the max charge of the capacitor. I'm not looking for...

The conservation of probability says: $$\partial_t J^{0} + \partial{i}J^{i} = 0$$ Use the Schrodinger equation to obtain$$ J^{i} (\vec r)$$. I have no idea where to start this kind of problem because the notation makes no sense to me. I would appreciate a hint or nudge in the correct direction.

Homework Statement Find currents I1 and I2 in the following circuit: Homework Equations I know I have to use Kirchoff's loop rule but I am not sure of the current going through the 5 ohm and 8 ohm resistors, is it just I1 and I2 respectively? Also do I incorporate the large loop at the...

A long horizontal wire carries 22.0A of current due north. What is the net magnetic field 20.0 cm due west of the wire if the Earth's field there points downward, 40 degrees below the horizontal, and has magnitude 5.0 E-5 T? My approach: 1. Drew north to the right and the wire lying flat, with...

Assume I have a parallel circuit of current sources with 5 current sources generating 1mA each. Therefore from both the terminals I will get 5mA total. Now if I add a battery to one of the terminals where current(i) will flow into my circuit. If i = 50mA, will I get 55mA current from another...

Hi everyone. I wanted to pose this question to those who are currently working as mathematicians (faculty members or postdocs, or those who finished their PhD and are working in industry), or current PhD students in math. Did you double major in mathematics and physics in your undergraduate...

Okay, so in Griffith's introduction to electrodynamics, Griffith clearly defines surface current density as follows: "when charge flows over a surface, we describe it by the surface current density, K. Consider a 'ribbon' of infinitesimal width dL running parallel to the current flow. If the...

There are two circuits, each consist of a cell and two bulbs, in one circuit they are in parallel, and in the other they are in series. What's the best way to remember which lamp has the greatest pd, current and resistance when one bulb is brighter than the other in the series and parallel circuit?

Homework Statement A capacitor is made of two parallel plates of area A, separation d. It is being charged by an AC source. Show that the displacement current inside the capacitor is the same as the conduction current. Homework Equations Idisp = ε(dΦE/dt) Q = CV C = Aε/d Xc = 1/(2πƒC) Q(t)...

Homework Statement The problem asks to find the Total Force on the Circuit Loop. I have a circuit loop with length 30.0 cm and width 10.0 cm with a current I2= 30.0 A that is flowing counter-clockwise. There is a wire that has the current I1=15.0 A flowing from left to right and is 7.50 cm from...

Homework Statement Two coils P and Q are placed close to one another, as shown in the first figure attached. The current in coil P is now varied as shown in the second figure. Show the variation with time of the reading of the voltmeter connected to coil Q for time t = 0 to time t = t 2...

Homework Statement See attached image for circuit diagram and givens. The switch has been closed for a very long time. a) What is the charge on the capacitor? b) The switch is opened at t=0 s. What current initially flows? Homework Equations V = IR Q=CV I=I0e-t/(RC) The Attempt at a Solution...

Homework Statement The value of the line integral around the closed path in the figure is 1.79×10−5 Tm . https://session.masteringphysics.com/problemAsset/1385538/4/32-22.jpg There is I2 and I3 inside the closed loop. I2 = 12 A What is I3? Homework Equations Amphere's Law: B = Uo I(enclosed)...

Hi all, I'm a current full-time employee in a calibration laboratory with a b.s. in applied physics. I see in my current position there is a ceiling for career opportunities and am looking to return to school for my masters. I feel that I would enjoy the clinical side of things, I consider...

Homework Statement A resistor connected across an AC power supply has a current given by I=(1.35A)cos(300t) when connected to a power supply with emf 120 V rms. Find the RMS current. Homework Equations IRMS=Imax/√2 The Attempt at a Solution IRMS=Imax/√2 IRMS=0.477 A INCORRECT Not exactly sure...

< Mentor Note -- thread moved to HH from the technical forums, so no HH Template is shown > Hi all, I'm trying to find an expression for the current i(t) as a function of C and V_out (t) after t = 0. I have an answer but still not sure at all if its correct or not. Here is my answer: I know...

Homework Statement An AC source was connected to a capacitor and an inductor (ignoring its ohmic resistance) in series. If the inductive reactance was equal to twice the capacitive reactance, and then the frequency duplicated, determine: 1. the relationship between the the current before and...

Hi. Why is it that in an autotransformer apparently most of the primary current goes through the winding and not through the load?

Could someone please explain to me what is the definition of a pulse current discharge, and what do we mean by pulse current discharge test ?

As the title states, can EMF = I = const ?

I'm looking for software that can simulate an ac circuit. After a quick google, I found several free online services (which I will try out). What I was wondering though is if anyone had some advice concerning my selection. A brief list of requirements: accurate simulation of different conductor...

Homework Statement I’m trying to understand what voltage is. Getting confused. I've written my confusion as questions below and answered the questions. (i) What is voltage? (ii) What is voltage passing through a lightbulb? (iii) Is POTENTIAL just another...

Homework Statement How to determine the current as a function of time that flows in 10 ohm resistor, 100 ohm resistor, and 15 microFarad capacitor? Please help Homework Equations I = V/R I_capacitor = I e^(-t/RC) The Attempt at a Solution I only know the equation V=IR and the capacitor...

Homework Statement (see attached file) Homework Equations Kirchhoff's laws The Attempt at a Solution (see attached file) I only included the work for measurement 1 since measurement 2 follows from that. I got both voltage values correct. However the paths of the current flow was incorrect...