Induced Definition and 925 Threads

Homework Statement Using the method of images: discuss the problem of a point-charge “q” inside a hollow, grounded, conducting-sphere-shell of inner radius “a”. That charge "q" is located at {\left| {{{{\bf{\vec r}}}_0}} \right|}. We don't care about its angular position. Oh yes: the problem...

Hi everyone, I'm working on COMSOL's ac-dc module and I'm trying to find the magnetic field which is created by an electrode pair (dipole). The working environment of the pair has nonzero conductivity and relative permittivity. I first found the current density between the electrodes in...

Homework Statement A bar of 1 m length aligned in y direction moves in +x direction at 10 m/s, in space where B = 1 T pointing in the -z direction. Calculate the motional EMF. If the bar above, is a part of a circuit with a light bulb of 10 ohms resistance, what would be the induced current...

I'm a bit confused about magnetism and electromagnetic induction. On the one hand I understand that to induce a current we need a change in magnetic flux. On the other... a charge moving relative to an external magnetic field experiences a force. If the field is uniform then we would...

There is well known pyroelectric effect in which polarisation of crystals occur under heat. I thought that pyroelectric could be good energy converter if not problems associated with it.Thus,heat should be applied in impulses and there might be a great looses associated with cycles.Also...

According to Nash theorem http://en.wikipedia.org/wiki/Nash_embedding_theorem" every Riemannian manifold can be isometrically embedded into some Euclidean space. I wonder if it's true also in case of pseudoremanninan manifolds. In particular is it possible to find a submanifold in...

Can anyone point me to a good site that explains current induction, specifically when a coil is placed around an energized, current carrying conductor? I would like to understand this principle to understand how power can measured in 3 phase power systems by using coils as a measuring element.

Hi, hopefully this is the right board to ask this on. I'm currently reading Groups, representations and Physics by Jones, and trying to get my head around induced transformations of the wavefunction. The problem is I seem to understand nearly all of what he's saying except the crucial part I...

my question is why oxygen lines does not appear in metal oxides spectrum taken at 532nm wavelength of Nd:YAG laser at atmospheric pressure. and what is the criteria for selecting emission lines for analysis?

Homework Statement C alculate the emf (in volts) induced in a loop of wire if the magnetic flux in the loop increases from zero to 71.1 milliweber in 16.7 millisec. Homework Equations faradays Law The Attempt at a Solution The only law I know is faradays law which uses Area...

I dabble in miniature milling/machining with my home CNC setup. I'm building a low temperature engine and have a question. The piston will be a neodymium magnet(s) set in graphite. Rather than using mechanical linkages and a crankshaft I want to use magnets to control the length of throw. By...

A recent explanation for "the majority of ball lightning observations": Is this plausible? A way to debunk this would be to find credible ball lightning videos(maybe on youtube), but i don't know if there are any.

A square loop of wire of side a is rotating with frequency \omega in a magnetic field. I understand that at time t, a magnetic field B=B_{0}sin\omega t passes through the loop. But why does the current induced in the loop vary twice with the frequency of rotation? What is the expression of...

I am trying to understand Lenz law as it applies to an A.C. generator, Lenz law says " an induced current is always in such a direction as to oppose the motion or change causing it". Does this mean that if the north pole of a magnet passes a conductor in a stator, that the current induced in the...

Homework Statement A flat coil of wire consisting of 20 turns, each with an area of 50 cm^2 is positioned so that the normal to its plane is at the angle of 30 degrees to a uniform magnetic field that increases its magnitude at a constant rate from 2.0T to 8.0T in 2.0 s. Homework Equations...

Homework Statement A 25-turn circular loop of wire has a diameter of 1m. In 0.2 seconds it is flipped 180 degrees at a location where the magnitude of the Earth's magnetic field is 50 micro T. What is the emf generated in the loop?Homework Equations -(dB/dt)(A)=VThe Attempt at a Solution When I...

Rotating Conducting Cylinder in B -- Induced Voltage [PLAIN]http://img690.imageshack.us/img690/2600/47007002.jpg I understand how to use motional emf to solve this problem. \int_C U \times B\, dl U = \omega R and \int_C dl = H so the answer, symbolically, is \omega RHB where \omega is the...

Homework Statement A metal loop is attached to an axle with a handle as shown. The north pole of a magnet is placed below the loop and the handle turned so that the loop rotates counterclockwise at a constant angular speed. On the two diagrams below, indicate the direction of the induced...

1. A 100-turn, 2.0-cm-diameter coil is at rest in a horizontal plane. A uniform magnetic field 60 degrees away from vertical increases from 0.50 T to 1.50 T in 0.60 s. 2. EMF = N*d(phi)/dt phi = flux = ABcos(theta) 3. dB/dt = 1/0.6 EMF = 1000*(1/0.6)*pi*r2*0.5 = 0.262 V Is...

Homework Statement The magnetic field inside a 5.0-cm-diameter solenoid is 2.0 T and decreasing at 4.90 T/s What is the electric field strength inside the solenoid at point on the axis?Homework Equations E=(r/2)*(dB/dt)The Attempt at a Solution E=(.025/2)*(4.9)= 0.06125 V/m Not sure what's...

A magnetic field B, that is decreasing with time is directed out of the page and passes through a loop of wire in the plane of the page, as in my drawing (ignore that the dots are not evenly spaced, you can only do so much in paint) Which of the following is true of the induced current in the...

Homework Statement A very thin conducting disc of radius a and conductivity \sigma lies in the x-y plane with the origin at its center. A spatially uniform induction is present and given by B=B_0 cos\(\omega t \)\hat{z}. Find the induced current density \vec{J} in the disc. Homework...

If anyone can advise that would be great. 1. The plane of a 5 turn coil of 5mm² cross sectional area is rotating a 1200 r.p.m in a magnetic field of 10mT. Q. Calculate the amplitude of the induced voltage across the coil Data: 5 turns c = 1200 rpm A = 5cm² B = 10 mT 2. φ =...

Homework Statement A coil is wrapped with 247 turns of wire on the perimeter of a square frame of sides 27.3 cm. Each turn has the same area, equal to that of the frame, and the total resistance of the coil is 2.53. A uniform magnetic field is turnedon perpendicular to the plane of the coil...

ok, if i have a rectangular loop parallel to the screen and in a uniform constant magnetic field pointing perpendicularly outwards of the screen, if i move the loop to the right of the screen, will there be an induced emf in the loop? my understanding is that there will be? because we have a...

Homework Statement A coil with 253 turns of wire, a total resistance of 28 Ohms, and a cross-section area of 0.36m^2 is positioned in a plane perpendicular to the field of a powerful electromagnet. What average current is induced in the coil during the 0.33s that the magnetic field drops...

Homework Statement A small magnetic moment \vec{m}(t) fixed at position \vec{r} varies in a complicated way as a function of time. (a) Show that if the time variation is "slow enough", the voltage generated around an arbitrary loop of wire near the origin is E(t)=\alpha...

I am a high school student, so forgive me if my question appears stupid. Consider a uniform magnetic field normal to the plane of the screen with varying magnitude. consider a point P on the screen in the magnetic field.the varying magnetic field will induce an electric field, with the field...

I have been trying to calculate the voltage and current induced in a stator by a rotor of permanent magnets. The formula Length x Velocity x the B-field , i understand most of. My question is about the Length part of the formula, in a stator the wire passes through the iron core, so is the...

Induced drag of an airfoil should be inversely proportional to velocity^2 wiki states "Since induced drag is inversely proportional to the square of the airspeed" Ok but [Induced Drag = 0.5 * Density * Velocity2 * Wing Area * Induced Drag Coefficient] which is proportional to the veloicty^2 and...

Ok... so there really isn't a homework problem that goes directly with what I am asking... I just want to understand how/why induction (magnet through a coil) gave certain results in our Science Workshop program... Here is what we did in our lab: We dropped a magnet (south end in first)...

Homework Statement A box of wire is moving within a constant B field. Is there an induced current? Homework Equations Slap rule The Attempt at a Solution Since the wire is experiencing constant B field, how would we figure out whether or not there is a current? I know there is a...

1. Homework Statement : A circular loop of flexible iron wire has an initial circumference of 166cm , but its circumference is decreasing at a constant rate of 13.0cm/s due to a tangential pull on the wire. The loop is in a constant uniform magnetic field of magnitude 1.00 T, which is oriented...

Homework Statement The area of a 100 turn coil oriented with its plane perpendicular to a 0.28 T magnetic field is 4.3×10−2 m^2. Find the average induced emf in this coil if the magnetic field reverses its direction in 0.36 s. Homework Equations E = -N (flux - flux initial)/(t-to)...

Homework Statement A conducting rod whose length is 25 cm is placed on a U-shaped metal wire that has a resistance of 8 ohm. The wire and rod are placed in the plane of the paper. A constant magnetic field of strength 0.40 T is applied out of the paper. An applied force moves the rod to the...

Hello everyone, This question is the third question from the 2001 IPhO: Problem text: http://www.jyu.fi/tdk/kastdk/olympiads/2001/IPhO2001-THEO.pdf Solution text: http://www.jyu.fi/tdk/kastdk/olympiads/2001/IPhO2001-THEO-SLN.pdf I'm having trouble understanding how they came to the conclusion...

This is an idea I had and felt it worth publishing. The reason fusion is so difficult is because the particles are so light, small, and have difficulty overcoming the coulomb barrier. Well I got to thinking and noticed that it'd be a lot easier to get heavy nuclei to fuse, but naturally they'd...

Homework Statement The setup is a pair of two circular wires, a small one of radius b and a large one with radius 2b, both sharing the same center and located on the same plane. There is a magnetic field of strength B within the smaller circle that comes out of the paper towards the observer...

Hi guys, can you guys point to me what are the recent experimental results that show that cells can be induced to make a pluripotent cells?

Homework Statement suppose that * is an associative binary operation on a set S. Let H = {a elementof S | a*x = x*a forall x elementof S}. Show that H is closed under *. Homework Equations The Attempt at a Solution i don't really know where to begin. I know i need to show forall...

hello I have a question. If 10V and 100mA is injected to GaAs laser ridge size is 1mm(length), 10um(width), 5um(thickness), which temperature can be generated in the ridge? the ridge is covered by gold for the electrical contact. Is it possible to calculate? I tryed to serch the...

Maybe a dumb question, and I've been wondering this a long time, but the Haiti thing reminded me... Is it possible for electronically produced frequencies to cause seismic activity? I know that injection wells/fracturing/oil & gas wells/dams can cause induced seismicity, but is there anyway at...

Can anyone point me in the right direction? I'm awful with electromagnetism.

Induced Voltage = -NBA/t I know the equation, but could someone please explain it to me?

Homework Statement See picture for clarity. There are 2 infinite wires carrying a current i, one wire does it in the upward direction and the other wire in the downward direction. They are separated by a distance L+2d. Between them lies a circuit such that the part that moves with a velocity v...

Homework Statement As shown in this picture: a 18 cm long solenoid with 1500 loops (N = 1500) and radius 2 cm is located at the center of wire frame (coil) that is 5(width) by 8(height) cm. There is a current inside of solenoid that is growing from 0 to 2.5 A in 7.5 seconds that rotates...

Homework Statement http://img697.imageshack.us/img697/2317/img11l.jpg (a = 0.10 m and b = 0.16 m) i=3t^3 - 5t (i - ampéres t - seconds) Determine the voltage induced in the coil to the instant t = 3 sec. well as the current direction. Homework Equations Hall efect The...

-ve sign in expression of "induced emf" What is the concept behind putting negative sign in: e=[SIZE="2"]-[rate of change of flux] Which direction does it signify?? How does direction affect the equation? How and where can we use negative sign in other expressions of induced emf??

Homework Statement A point charge q is situated a large distance r from a neutral atom of polarizability \alpha. Find the force of attraction between them. Homework Equations \vec{E}_{mono}(r)=\frac{q}{4\pi\epsilon_0r^2}\hat{r}...

when a current in a coil induces a current in another that is in series with it. Would the direction of the induced current change if the current falls? With Lenz's law the induced current would oppose the current of the first coil but what would happen to the induced current if the switch...