Electromagnetic Induction Physics Example 3

Follow the full solution, then compare it with the other examples linked below.

Example 3

medium
A bar magnet is pushed into a coil of 100100 turns, increasing the flux through each turn from 00 to 0.004 Wb0.004 \text{ Wb} in 0.2 s0.2 \text{ s}. What is the induced EMF? If the coil has resistance 5 Ω5 \text{ } \Omega, what current flows?

Solution

  1. 1
    Induced EMF: E=NΔΦΔt=100×0.0040.2=100×0.02=2 V\mathcal{E} = N\frac{\Delta\Phi}{\Delta t} = 100 \times \frac{0.004}{0.2} = 100 \times 0.02 = 2 \text{ V}.
  2. 2
    Induced current: I=ER=25=0.4 AI = \frac{\mathcal{E}}{R} = \frac{2}{5} = 0.4 \text{ A}

Answer

E=2 V,I=0.4 A\mathcal{E} = 2 \text{ V}, \quad I = 0.4 \text{ A}
Pushing a magnet into a coil changes the flux and induces an EMF. The induced current creates its own magnetic field that opposes the magnet's motion (Lenz's law), requiring effort to push the magnet in.

About Electromagnetic Induction

The process by which a changing magnetic flux through a conducting loop produces a voltage (electromotive force, EMF) across the conductor, which can drive an.

Learn more about Electromagnetic Induction →

More Electromagnetic Induction Examples

Example 1 easy

A single loop of wire with area [formula] is in a magnetic field that changes from [formula] to [for

Example 2 medium

A coil with [formula] turns and area [formula] is rotated from perpendicular to parallel to a [formu

Example 4 hard

A rectangular loop ([formula]) moves at [formula] into a region with a uniform [formula] magnetic fi

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