Induced current Definition and 202 Threads

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. N

    How to find the maximum induced current for a diamond-shaped loop?

    Homework Statement Find the total maximum induced current for the diamond-shaped metal loop that is moving at a speed of 10 m/s towards a uniform magnetic field of 0.8T. All four lengths equal 10 cm or 0.01 m. Homework Equations emf = -dΦB/dt ΦB=∫B*dA A = (1/2)bh The Attempt at a Solution I...
  2. dumbdumNotSmart

    Induced current of a coil on another coil

    Homework Statement We have two coils of copper wire, drawn below. One has a battery connected to it. The other one has a galvonometer connected. If the coil with the voltage is moved closer as shown in the picture, with considerable velocity, what direction will the current induced on the other...
  3. Casalino F

    Changing cross-sectional area effect on induced current

    Recently I did an experiment where I dropped a magnet through a tube that was surrounded by a coil, and I hoped to investigate a factor that would affect the current induced (Faraday's law). I chose to study the effect that changing the cross-sectional area of the wire had on the induced...
  4. EddieP

    How does the core size affect an Inductor's efficiency?

    Hello, I am wondering if anyone can help me with the following question. I want to find out how the size of the core in an inductor influences the current induced in the secondary coil, and whether a smaller core is more efficient if efficiency is defined as inducing the highest current in the...
  5. O

    How is there not an infinite regress in the EMF of a motor?

    Say we have a coil connected to a battery in a uniform magnetic field, perpendicular to the magnetic moment of the coil. This is a simple motor. There is a torque on the coil that varies with the angle θ between the field and the moment. Clearly, the angular velocity ω is not constant. Here is...
  6. S

    Magnetic field change for induced current

    Homework Statement A uniform magnetic field is perpendicular to the plane of a circular loop of diameter 10 cm formed from wire of diameter 2.5 mm and resistivity 8.5×10-8 Ω·m. At what rate must the magnitude of the magnetic field change to induce a 10 A current in the loop? Homework Equations...
  7. P

    What Rate of Magnetic Field Change Induces a 10 A Current in a Circular Loop?

    Homework Statement A uniform magnetic field is perpendicular to the plane of a circular loop of diameter 18 cm formed from wire of diameter5.0 mm and resistivity 1.69 ✕ 10−8 Ω · m. At what rate must the magnitude of change to induce a 10 A current in the loop Homework Equations Φ = ∫ B ⋅ dA...
  8. M

    Help with magnetic induction and finding induced current

    Homework Statement I have attached a picture that details the problem. This is my practice test and I have no clue what I am doing wrong. Essentially a loop of wire is moving in constant velocity into a magnetic field. The magnetic field lines are pointing into the page. The problem is...
  9. E

    Electrical energy converted to heat in coil

    Homework Statement Given a coil with N turns, a radius of r, a resistance of R', and an induced current i'(t) running through the coil, determine the totale energy converted to heat in the coil for t>=0.EDIT: The circuit on figure 4 consists of a resistance R and a capacitor with capacitance...
  10. H

    Current induced in concentric superconducting loops

    Homework Statement Suppose you have two superconducting loops, concentric, in a plane. Also suppose that their radii, R2 (outer) and R1 (inner) have the same order of magnitude (so you can't assume B through the inner loop is constant everywhere over the inner loop's surface.) If a constant...
  11. K

    SAT II Physics -- Induced current in loop (Faraday's law)

    Homework Statement A loop of wire and a bar magnet are moving relative to one another. Which motion in the diagrams shown below will NOT induce a current in the loop? Homework Equations Lenz's Law: A changing magnetic field can induce a current in a direction that produces its own...
  12. Q

    Induced Current in Square Loop

    Homework Statement A 21cm×21cm square loop has a resistance of 0.12 Ω . A magnetic field perpendicular to the loop is B=4t−2t^2, where B is in tesla and t is in seconds. (A) What is the current in the loop at t=0.0s? (B) What is the current in the loop at t=1.0s? Homework Equations for a...
  13. PhiowPhi

    Eddy currents, and induced current, can they both co-exist?

    Im a bit confused about one point. Can Eddy current, and induced current exist at the same time...? If a conductor is a part of a closed circuit, and there is a change in magnetic flux over time, both Eddy current and induced current would oppose that change? Let's assume a conductor that is a...
  14. Kerrigoth

    Are induced currents created by motion or change in flux?

    The book I am working through is beginning to dive into induced currents and Lenz's Law. When a conductor is moving perpendicular to a magnetic field, the charge carriers inside will experience a magnetic force; This causes the charges to move. Eventually, the electric field from the charge...
  15. nawand

    What is the direction of induced current

    Homework Statement Use Lenz’s law to answer the following questions con- cerning the direction of induced currents. Express your answers in terms of the letter labels a and b in each part of Figure P31.22. (a) What is the direction of the induced current in the resistor R in Figure P31.22a when...
  16. cnh1995

    Induced current in a circular loop

    Hi friends..I'm struggling with an interesting puzzle...Suppose there is a circular conducting loop of radius 1/π cm, one half of which is made of a material with resistance 1Ω and the other half from a material with resistance 5Ω. If somehow, one managed to set up a changing magnetic field...
  17. T

    Ampere's law and induced current

    Homework Statement Homework Equations ∫BdL = μI The Attempt at a Solution a) the magnetic field is a circle around the wire so the length of the path is the circumference of the circle which is 2πr ∫BdL = BL = μI B(2πr) = μI B = μI/2πr in this problem it is into the page (right hand rule)...
  18. I

    Induced current from changing magnetic field

    Homework Statement Homework Equations emf = i (induced) R emf = - d(Ф)/dt Ф = B (dot) A B = μi/(4piR) The Attempt at a Solution emf = - d(Ф)/dt emf = - d( B (dot) A )/dt emf = - d[ (μi/(4piR) * A ]/dt, A and B are perpendicular Really not sure how to proceed from here as there are...
  19. blooperkin

    Explaining the Decrease in Current in a Rotating Motor

    Homework Statement The armature of a simple motor consists of a square coil and carries a current of 0.55 A just before it starts to move. The coil is positioned perpendicular to a magnetic field. Explain briefly why the current falls below 0.55A once the coil of the motor is rotating...
  20. ELB27

    Energy gained from induced current

    I have a confusion about the energy effects of current induction. Suppose I place a coil of wire near a long, high-voltage AC power-line. The changing current and hence, the changing magnetic field it produces will induce current in my coil. Then, I can connect the coil to a resistor and get...
  21. arpon

    Does Increasing the Area of a Loop in a Magnetic Field Induce Current?

    Homework Statement [/B] Suppose, there is a 'constant' magnetic field ##B## in the upward direction. A loop of conductive wire(XYZ in the picture, which is connected to a closed circuit with resistance R) is placed horizontally on it. The area of the loop is being increased with time. Will...
  22. A

    Induced Current in an AC generator

    Homework Statement This is a simple inquiry, based on what my textbook has told me. "...the amount of induced current also depends on the angle of the conductor in relation to the external magnetic field. The induced current is at a maximum when the plane of the loop is parallel to the...
  23. B

    Induced Current problem from review

    Homework Statement A 40 turn circular coil of a 4.0 cm radius and a total resistance of 0.20 Ω is placed in a uniform magnetic field directed perpendicular to the plane of the coil. The magnitude of the magnetic field varies with time as B = 50*sin(10π*t) mT where t is measured in s. What is...
  24. PhiowPhi

    Induced current of this conductor?

    I have a confusing example that I'm studying, I tried to figure out the direction of induced current. But the right hand rule would tell me there isn't, but there has got to be since there is change in flux?! Here is the example: The gray bar is the conductor that is moving through a...
  25. A

    Magnitude of induced current

    A simple experiment of pushing magnet bar into solenoid & pulling it out from solenoid. If galvanometer is used to measure magnitude of induced current, galvanometer will show greater deflection when the bar magnet is pushed into the solenoid but the deflection will be less when the magnet is...
  26. C

    Point charge induced current on a conducting ring

    Hello, I have a conducting copper ring of inner radius a and outer radius b. point charges Q pass through the centre of this ring for time dt. so I guess I'm suppose to get a step function of induced current or something similar. 1)what is the equation relating the charge Q to the...
  27. T

    Induced current and torque in a rectangular metal loop

    Homework Statement (a) The metallic rectangular loop of length b and width a (ABCD) is mounted in an assembly, which allows it to be rotated about an axis bisecting AD and BC. The plane of the loop makes an angle θ to the horizontal and a uniform magnetic field B is applied vertically...
  28. M

    Calculating Induced Current in a Circular Coil with Time-Varying Magnetic Field

    Homework Statement A circular coil has N equal loops with diameter C. Each loop has resistivity η and diameter d. There is a field on the central axis of B(t) = B_0 sin(ωt). Find the induced current (ignoring other fields) Homework Equations emf = -d/dt * flux(t) i = emf/R R = η*l/AThe...
  29. 1

    Finding direction of induced current

    Homework Statement The right side of a wire loop is dragged to the left across the south pole of a magnet. What will be the direction of the current induced in the loop? a. No current will flow around loop. b. Current will move in the wires of the loop in the same direction as the loop...
  30. 1

    No Induced Current in a Moving Magnet?

    Homework Statement In which of the following will a current NOT be induced in the conducting loop? a. Magnet moving toward upright conducting loop of wire b. Magnet moving away from an upright conducting loop of wire c. Magnet moving toward a horizontal conducting loop of wire d...
  31. S

    Finding The Induced Current in This Loop

    Homework Statement Hey guys, I have a physics II test tomorrow on Electricity and Magnetism, and I cannot seem to figure out this question. The rectangular loop in the figure has 2.2×10−2Ω resistance. What is the induced current in the loop at this instant? Picture: Homework...
  32. L

    Induced current in a coil around a solenoid

    Homework Statement A coil with 150 turns, a radius of 5.0 cm, and a resistance of 12 Ω surrounds a solenoid with 300 turns/cm and a radius of 4.3cm; see the figure. The current in the solenoid changes at a constant rate from 0 to 1.8 A in 0.12 s. Homework Equations B from solenoid =...
  33. B

    Relationship between Induced Current and Current in a Wire

    Homework Statement A long straight wire carries a steady current. A square conducting loop is in the same plane as the wire. If we push the loop toward the wire, how is the direction of the current induced in the loop related to the direction of the current in the wire? Homework...
  34. V

    Need help on electromagnetic poles and induced current

    Hello, I know the magnetic field produced by a direct current flowing through a solenoid has a north and south pole, so how about the magnetic field produced by a current flowing through a straight conductor, does it have a north and south pole too? If it have them, where is it located? A...
  35. amjad-sh

    The induced current in transformer

    Hello, I know that in ideal transformer the law I2/I1 = N1 /N2 I know that I2 is the induced current in the secondary coil, so I1 is the induced current in the primary coil or the current generated from the generator?? where N1 is the number of turns in the primary coil. and N2 is the number...
  36. V

    Average induced EMF and average induced current of a flipped loop?

    Homework Statement A wire loop of resistance R and area A has its normal along the direction of a uniform magnetic field, B. The loop is then flipped over in a time Δt so that its normal is opposite to the field. a) Calculate the average induced EMF. b) Find the average induced current. c) If...
  37. Z

    Induced Current Due to a Solenoid

    Homework Statement An aluminum ring of radius 5.00 cm and resistance 3.00 × 10–4 Ω is placed on top of a long air-core solenoid with 1 000 turns per meter and radius 3.00 cm. Over the area of the end of the solenoid, assume that the axial component of the field produced by the solenoid is half...
  38. T

    How to determine the direction of induced current in a solenoid?

    I have come across this problem, who to determine the direction of induced current. It keeps me wondering why the answer that i got is Fleming's right hand rule? Aren't it should be Right hand grip rule? Cz the usual and conventional way of inducing electricity in a solenoid is to pass the...
  39. A

    Direction of induced current in conducting ring due to motion of bar m

    Homework Statement Homework Equations - The Attempt at a Solution The relative velocity of magnet with respect to ring is 5−4=1m/s How can I find the Direction of induced current in conducting ring due to motion of bar magnet? I searched online and found this ...
  40. PsychonautQQ

    Why is the Induced Current Clockwise in this GRE Problem?

    Homework Statement http://grephysics.net/ans/9277/54 I am confused about this. The explanation for why the induced current is clockwise is because the induced current would resist the change in magnetic flux, therefore work to increase the magnetic field. But if the current induced in the...
  41. S

    Why will there be no induced current?

    Why will there not be an induced current in a field parallel to a current carrying wire?
  42. P

    Induced current & force between 2 wires

    These are 2 straight wires parallel for 3 inches. Specifically a 6AWG and 12AWG separated approximately 2 inches. A surge current enters on the 6AWG which has a rising edge of 2500A/us. This is for a surge device ... I have been working in plain old RF for too long to be certain that I using...
  43. P

    Induced Current Problem(Electromagnetism)

    Homework Statement A small, 1.60-mm-diameter circular loop with R = 1.40×10−2Ω is at the center of a large 120-mm-diameter circular loop. Both loops lie in the same plane. The current in the outer loop changes from 1 A to -1 A in 8.00×10−2 s. What is the induced current in the inner...
  44. skate_nerd

    Induced current with two solenoids

    Homework Statement so there's two solenoids on the same axis of symmetry, and the smaller one inside the larger one has a resistance of 11 ohms, 1000 turns, and radius .02 meters. the outer solenoid has n 18000 turns per meter, and had a current that is increasing at a constant rate with...
  45. F

    Direction of the induced current and polarity

    Homework Statement http://img805.imageshack.us/img805/6030/82154948.png Find Vemf (between points 1 and 2) and it's polarity at t = 0. I have omitted details because my question is specifically on the polarity.Homework Equations Lenz's law: An induced electromotive force (emf) always gives...
  46. A

    Induced Current for a Solenoid Pulled Away From Loop

    Homework Statement Sorry for the blurry picture. If the coil is being pulled away from the loop shown to the right, in what direction is the current induced in the loop? Homework Equations right-hand rulesThe Attempt at a Solution I assumed it to be clockwise just from looking at the...
  47. C

    Magnetic field in a solenoid due to induced current in a coil

    Homework Statement A coil of wire with N turns is placed around the a long solenoid with n turns per unit length carrying a current I as shown below, A)If a current I flows through the solenoid, derive an expression for the magnetic flux through the coil and explain why the size and shape...
  48. D

    Induced current on a metallic ring

    I've just got confused about how the induced current in a metallic ring is calculated. Consider a metallic ring (radius a, resistance R and inductance L) immersed in a oscillating magnetic field, which is oriented orthogonally to the plane of the ring. The variation in flux of magnetic...
  49. D

    How Does Coil Winding Affect Induced Current in Generators and Solenoids?

    Homework Statement http://img831.imageshack.us/img831/9721/img20120725160304.jpg http://img542.imageshack.us/img542/653/img20120725160312.jpg Fig 1 is an AC generator Fig 2 shows 2 solenoids (ASSUME the area of coils in both fig1 and 2 are the same = A, resistance of 3-turn coils = R)...
  50. L

    Induced Current and Eddy Current

    Homework Statement I want to know whether Eddy current and Induced Current are same? Homework Equations The Attempt at a Solution 1)When flux linked with a circuit changes, an emf is induced in the circuit and this emf is called induced emf and the current is called induced...
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