Faraday's Law Physics Example 1

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

Example 1

medium
A coil with 100100 turns experiences a change in magnetic flux from 0.05 Wb0.05 \text{ Wb} to 0.02 Wb0.02 \text{ Wb} in 0.1 s0.1 \text{ s}. What is the induced EMF?

Solution

  1. 1
    Faraday's law: E=−NΔΦΔt\mathcal{E} = -N\frac{\Delta \Phi}{\Delta t}.
  2. 2
    Change in flux: ΔΦ=0.02−0.05=−0.03 Wb\Delta \Phi = 0.02 - 0.05 = -0.03 \text{ Wb}.
  3. 3
    E=−100×−0.030.1=−100×(−0.3)=30 V\mathcal{E} = -100 \times \frac{-0.03}{0.1} = -100 \times (-0.3) = 30 \text{ V}

Answer

E=30 V\mathcal{E} = 30 \text{ V}
Faraday's law states that a changing magnetic flux through a coil induces an EMF. More turns and faster flux changes produce larger EMFs. This is the basis of electric generators.

About Faraday's Law

The induced EMF in a circuit equals the negative rate of change of magnetic flux through the circuit.

Learn more about Faraday's Law →

More Faraday's Law Examples

Example 2 hard

A single loop of area [formula] is in a magnetic field that increases uniformly from [formula] to [f

Example 3 medium

A coil of [formula] turns has an area of [formula]. The magnetic field through it decreases from [fo

Example 4 medium

A coil of [formula] turns has a magnetic flux that changes from [formula] to [formula] in [formula].

Example 5 hard

A square coil with 200 turns and side length [formula] is in a magnetic field that decreases uniform

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