What is Induced current: Definition and 201 Discussions

Electromagnetic or magnetic induction is the production of an electromotive force across an electrical conductor in a changing magnetic field.
Michael Faraday is generally credited with the discovery of induction in 1831, and James Clerk Maxwell mathematically described it as Faraday's law of induction. Lenz's law describes the direction of the induced field. Faraday's law was later generalized to become the Maxwell–Faraday equation, one of the four Maxwell equations in his theory of electromagnetism.
Electromagnetic induction has found many applications, including electrical components such as inductors and transformers, and devices such as electric motors and generators.

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  1. D

    How Does a Moving Conducting Loop React to a Uniform Magnetic Field?

    A region of space d = 35 cm wide is filled with a uniform magnetic field B = 2.3 T oriented normal to the plane of the screen and pointed into the screen. There is no magnetic field to the left or to the right of this region. An external agent drags a rectangular conducting loop with dimensions...
  2. L

    Direction of induced current question

    Homework Statement There is a conductor; a metal pole say, in between a north and south magnets. North on the left, south on the right. The conductor is layed out in such a way that it is perpendicular to the magnetic field lines going from north to south. Let's label the metal poles X for...
  3. I

    Ampere's Law (I think). Induced current from current carrying wire

    Homework Statement A 1.60 cm x 1.60 cm square loop of wire with resistance 1.10 \times 10^{-2} \Omega is parallel to a long straight wire. The near edge of the loop is 1.10 cm from the wire. The current in the wire is increasing at the rate of 100 A/s Homework Equations I think I have...
  4. W

    Induced current in long straight wire

    Homework Statement A current is induced in a loop by something happening with current in a long straight wire near the loop. What could be happening? (There are two possibilities. Neither the wire nor the loop is moving.) Homework Equations Ampere's Law Faraday's Law The Attempt...
  5. J

    Which Hand Rule Determines Current Direction in Magnetic Fields?

    Please see question at . . . . http://www.flickr.com/photos/37144556@N07/3476115300/sizes/o/ (i) I am not sure which hand rule to use?? I think its the right hand rule, so does that mean the answer to question (i) is clockwise. (ii) is the answer " in a circluar direction perpendicular...
  6. R

    Faradays Law - Induced Current

    Homework Statement A loop of wire is situation between a wire (Wire 1) that is perpendicular to the loop and another wire (Wire 2) that is parallel to the loop (the diagram has the loop and Wire 2 in the plane of the page, Wire 1 is running "through" the page). Is a current induced, and in...
  7. E

    How Is Induced Current Calculated in a Rectangular Loop?

    Homework Statement The rectangular loop shown has resistance 20.0 mΩ. Determine the induced current in the loop at the instant shown. Answer: 66.7µA http://img264.imageshack.us/img264/7386/picture1nlz.png Homework Equations induced emf = |d(flux)/dt| I = emf / R The...
  8. P

    Direction of induced current - VERY basic

    Homework Statement A current loop with area A is placed in region II in the x-z plane, centered at the origin. (Below is a view looking down from y > 0.) If the magnitude of the current per unit length in each sheet is increased (the directions stay the same), the induced current in the loop...
  9. B

    Induced current in parallel loop

    Homework Statement The drawing below shows a circular loop of wire (raadius 0.15m) connected to a power supply. The top loop is directly over the bottom loop, which is not connected to anything. In the picture, the loops are shown parallel with one over the other, with the perspective...
  10. N

    Magnetic Flux and Induced Current

    Homework Statement The drawing shows a bar magnet falling through a metal ring. In part a the ring is solid all the way around, but in part b it has been cut through. (a) Explain why the motion of the magnet in part a is retarded when the magnet is above the ring and below the ring as well...
  11. S

    Calculating Induced Current in a Rectangular Loop

    Homework Statement A WxH rectangular loop of wire, with resistance R, lies on a table a distance s from a separate long straight wire carrying a current I. If the loop is pulled to the right, parallel to the wire, with the speed v, then what is the magnitude of the current induced on the...
  12. J

    EMI - induced current on two parallel wire

    I would like to quantify the EMI on a circuit and I am confused on how to do that. I have two parallel wires that are laying on top of each other. I have tried to calculate the flux linkage and came up with: \Lambda = [l*\muo*I/(2pi)]*ln((d-a)/a) where a=radius of each wire...
  13. S

    EMF and induced current question

    The rectangular loop in the figure has 1.7×10^−2 ohm resistance. What is the induced at this instant? See picture below. Answer is in terms of I, like 5*I. emf = Bvl I= emf/R B= [\mu_0 / 2*pi] *I * ln(.03/.02) since the magnetic field goes through the loop from 2cm to 3cm then I used...
  14. T

    Induced Current in a Circuit

    Homework Statement A two-loop wire circuit is 53.4069 cm wide and 35.6046 cm high. The wire circuit in the figure is located in a magnetic field whose magnitude varies with time according to the expression B = (0.001 T/s) t and its direction is out of the page. Assume The resistance per...
  15. J

    Induced current of a coil surrounding a solenoid

    Homework Statement A coil with 170 turns, a radius of 5.0 cm, and a resistance of 12 ohms surrounds a solenoid with 230 turns/cm and a radius of 4.7 cm; see the figure. The current in the solenoid changes at a constant rate from 0 to 1.8 A in 0.11 s. Calculate the magnitude and direction of...
  16. P

    What Is the Direction of Induced Current in Copper and Glass Tubes?

    Homework Statement A magnet is dropped down each the copper and glass tube. What direction is the induced current in the copper and glass tube respectively? a)clockwise, clockwise b)clockwise, no induced current c)counter clockwise, clockwise d)counter clockwise, no induced current...
  17. J

    Induced current through a resistor - with variable resistor and two coils

    Homework Statement The two solenoids in the figure are coaxial and fairly close to each other. While the resistance of the variable resistor in the left-hand solenoid is increased at a constant rate, the induced current through the resistor R will A - flow from a to b. B - flow from...
  18. R

    Exploring the Possibilities of Induced Currents in Magnetic Fields

    Will this work in principal? When a current is induced into a coil, by way of a permanent magnet, the said coil will react in producing its' own flux field. Can the flux field produced further induce a current in, let's say, a separate/independent closed loop? Thanks
  19. M

    Transformers and induced current

    Hello. 3) A step up transformer increases the mains voltage of 230V to 5000V. a) calculate the ratio Number of primary turns/Number of secondary Turns I know the formula input voltage/output voltage = Primary turn/ Secondary Turns So i did 230/5000 = 0.046. This as a fraction is...
  20. V

    Induced current in copper wire

    Homework Statement A square loop, 5.3 m on a side, is made of copper wire, 0.9 mm in radius. A 3.2 T magnetic field, perpindicular to the loop is increasing at the rate of 0.29 T/s. The resistivity of copper is 1.7 x 10^-8 ohm*m. Find the induced current. Answer in units of A. Homework...
  21. S

    Induced current and voltage, magnetism

    Homework Statement a single square loop of high resistivity wire ( rho = 10^-6 ohm-meters) is placed in a constant magnetic field B of 0.3 Teslas and oriented so that the axis of rotation of the loop is perpendicular to B and in the plane of the loop. the loop rotates with an angular frequency...
  22. F

    Question about induced current

    Say we have an induced circuit. My book states that we cannot use the loop rule on an induced circuit because we cannot define a potential difference in the circuit. If the potential difference is undefined how can current exist? There's probably a really obvious answer, but I'm not seeing it.
  23. O

    An application of induced current

    sorry all, I'm hit by a barrage of lab questions that demand an understanding of this that i can't learn out of the book :( so we're "wiretapping" into a speaker (completely lame i know) with coils of wire running through it. we can have the coil in one of four configurations 1. be...
  24. G

    Induced Current circuit problem

    The circuit is shown below: Find the current through section PQ of length a = 65.0cm. The circuit is located in a magnetic field whose magnitude varies with time according to the expression B = (1.00 x 10^-3T/s)t. Assume the resistance per length of the wire is 0.100 Ohm/meter...
  25. H

    Induced Current in Outer Coil - Solution Explained

    [SOLVED] Induced Current Homework Statement If I have a scenario where one coil is insider another, in which of the following cases will the induced current in the outer coil be the greater? The Attempt at a Solution I would say when the current in the inner coil is increasing rapidly, but I...
  26. P

    Moving while lighting, will be induced current in me?

    ometimes people say that if you moving while lighting, there will be current induced in you, and you'll die, is it correct, and if so how the electrical circuit is closed? (They say if lighting strikes near you, from the electrical field, if you move, there will be induced current in you)
  27. S

    Induced Current in a Circuit by a Moving Magnet

    A 10-cm-wide, zero-resistance slide wire is pushed toward a 2.0 ohm resistor at a steady speed of 0.50 m/s. The magnetic field strength is 0.50 T. How much power does the pushing force, 6.25*10^-4 supply to the wire? What is the magnitude of the induced current? I got 3.13*10^-4 for the...
  28. R

    Direction of induced current

    Just need to know if current goes from x to y or y to x. using right hand rule with my thumb pointing towards y and my fingers pointing down (in direction of flux lines) and my palm pointing in direction of force which is straight into the magnet indicates current is in the direction of my...
  29. W

    Lenz's Law: Direction of Induced Current

    Homework Statement 15. According to Lenz's law, the direction of an induced current in a conductor due to a change in the magnetic field near the conductor will be that which tends to produce which of the following effects? a. Enhance the effect which produces it b...
  30. K

    What is the magnitude of the induced current in the coil

    The component of the external magnetic field along the central axis of a 50−turn coil of radius 5.0 cm increases from 0 to 1.0 T in 4.3 s. (a) If the resistance of the coil is 2.9 Ω, what is the magnitude of the induced current in the coil? (b) What is the direction of the current if the axial...
  31. M

    Calculating EMF Induced Current in a Circular Loop of Wire

    Homework Statement The magnetic field perpendicular to a circular loop of wire 23 cm in diameter is changed from +0.52 T to -0.45 T in 175 ms, where + means the field points away from an observer and - toward the observer. Homework Equations (pardon me with the equations, I am LaTeX...
  32. J

    Induced current in a wire multiple choice question

    question In a particular experiment a long length of copper wire of very low resistance is rotated by two students. The ends of the wire are connected to a galvanometer, G, and a current is detected. Which of the following is LEAST likely to affect the amount of current produced? (A) The...
  33. S

    Solving for Induced Current in a Plane Loop Wire: Faraday's Law

    Here is a question I have on a practice exam that I am having a littel trouble with. A plane loop of wire consisting of a single turn if radius 5cm is perpendicular to a magnetic field that increases uniformly in magnitude from 0.5T to 2.5T in 1.5 seconds what is the resluting indiced current if...
  34. P

    Induced Current in Aluminum Ring Around Solenoid

    An aluminum ring of radius 5 cm and resistance 0.003 ohms is placed around the center of a long air-core solenoid with 1000 turns per meter and a smaller radius of 3 cm. If the current in the solenoid is increasing at a constant rate of 270 A/s, what is the induced current in the ring? B=...
  35. W

    What is the direct of the induced current in the circular loop

    I'd really appreciate some help with the following questions. Q1) What is the direct of the induced current in the circular loop due to the current shown in each part of the following fig?Have attached pics of 2 questions. The one on top has I increasing and one on the bottom has I decreasing...
  36. X

    How Is Induced Current Calculated in a Ring Near a Moving Magnetic Dipole?

    i am trying to solve for the induced current for the following situation: a magnetic dipole, \vec{m}=m_{0}\hat{z} moving with constant velocity coaxially with thin conducting ring. the ring has a resistance r and self-inductance L. what I've done is take the magnetic field of the dipole...
  37. P

    Why Is Fleming's Right Hand Rule Applied to Loop AD in a Moving Circuit?

    In my figure, the whole circuit is being pulled to the right. AD experiences no change in magnetic field. Why do we apply the Fleming's right hand rule on the loop AD instead of BC? And, if the whole circuit is moving in the uniform magnetic field, if the shape of the circuit is like the...
  38. bayan

    Identifying Direction of Induced Current - Physics Exam Prep

    Hi guys. I have a physics exam coming up in about 4 days. I have tried to learn how to identify the direction of induced current. But still I have to guess the direction which is not helpfull. I was wondering if you could give me a link that illustrates how to identfy the direction or perhaps...
  39. B

    Calculating Induced Current in Coaxial Solenoid-Wire System

    I'm working on a question that I could use some help on. The problem basically says there is a solenoid with a current running through it given by an equation. There is a wire that is coaxial with and surrounding the solenoid, and the wire makes two loops around the solenoid. A resistance for...
  40. bayan

    Magnetic fields & induced current.

    would increasing the speed at which magnet passes through a coil Increase,Reduce or does not change the amount of electromagnetic induction? cheers personally I would go with increase but want to see if I am right
  41. M

    Magnetic flux and direction of induced current

    I am really really hoping that the answer is wrong in the back of my book otherwise my entire basis for electricity/magnetism will be shattered :cry: Basically, there is a picture of a magnetic field going into the page, and there is a coiled loop within this magnetic field. If the...
  42. P

    Increasing Induced Current in Mutual Induction

    In mutual induction, how can we increase the induced current, not e.m.f.?
  43. M

    Quick induced current from magnetic field question direction of current?

    With RHR-1, if the rod moves to the right in a field coming into the page, the force will move positive charge up (in reality move negative electrons down) in the rod, and induce a current but why is the current counter clockwise?
  44. M

    Phys: Induction and Induced Current (2 loops)

    I've been having trouble with the solution my book (and the solution manual) gives for a problem. Basically, there are two inductors (wire coils): one is on the left, hooked to a battery and a switch. Then there's one to the right of it, hooked to only a resistor. The left switch is closed...
  45. S

    Current vs. Induced Current: What's the Difference?

    If a switch of a circuit system of a wire loop is open, then no current flows. There would also be no magnetic flux and induced current if it remains open, right? What is the difference between current and induced current? I know the latter arises from a change in the magnetic field, but what...
  46. J

    How Does a Time-Varying Magnetic Field Induce Current in a Circuit?

    This one is really getting to me. Find the current through section PQ (the middle column of the circuit) of length a, a =.65 m. The circuit is located in a magnetic field whose magnitude varies with time according to the expression B(t) = .001t. Assume the resistance per length of wire is...
  47. P

    Problems concerning magnetic fields, induced current, emf

    I been trying to work out these problems for the past two days but cannot come up with a solution. If anyone can help that would be greatly appreciated. 1) A 3.80-g bullet moves with a speed of 180m/s perpendicular to the Earth’s magnetic field of 5.00 X 10-5 T. If the bullet possesses a net...
  48. D

    Finding Induced Current Density (J) in a Cylinder under a Magnetic Field

    Given a cylinder of length L, radius a and conductivity sigma, how does one find the induced currenty density (J) as a function of p when a magnetic field B is applied? Where p is the distance from the axis of the cylinder and B is applied along the axis of the cylinder, B = Bosin(wt)...
  49. B

    Magnetic Field and induced current

    Can anyone help me to do this problem. Thanks in advance. A closed wire loop in the form of a square of side 4.0cm is mounted with its plane horizontal. The loop has a resistance of 2.0*10^(-3) ohm. The loop is situated in the magnetic field of strength 0.7 T directed vertically downwards...
  50. V

    A few basic induced current questions

    It's sunday night and I have another prelab to do. I wrote down all the answers I thought were correct but I'd like a little confirmation on these. See attached picture for the setup. The red lines indicate parts where the coil is looped away from the view and the black would be parts of the...
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