Physics – 4.5.1 Electromagnetic induction | e-Consult

The magnitude of the induced e.m.f. is affected by the following factors:

• Strength of the magnetic field (B): A stronger magnetic field will produce a larger induced e.m.f. This is because a stronger magnetic field exerts a greater force on the moving charges within the wire, leading to a greater displacement of electrons and thus a larger induced voltage.
• Speed of movement of the coil (v): A faster speed of movement of the coil through the magnetic field will produce a larger induced e.m.f. This is because the coil cuts through more magnetic flux per unit time, increasing the rate of change of magnetic flux and therefore the induced voltage.
• Number of turns in the coil (N): A larger number of turns in the coil will produce a larger induced e.m.f. Each turn of the coil experiences the magnetic flux, and the e.m.f. in each turn adds up, resulting in a larger overall induced e.m.f.
• Area of the coil (A): A larger area of the coil exposed to the magnetic field will produce a larger induced e.m.f. This is because a larger area intercepts more magnetic flux, leading to a greater rate of change of flux and a larger induced voltage.

These factors are related by Faraday's Law of Induction: ε = -N(dΦ/dt), where ε is the induced e.m.f., N is the number of turns, and dΦ/dt is the rate of change of magnetic flux. The magnetic flux (Φ) is given by Φ = B A cos θ, where θ is the angle between the magnetic field and the area vector of the coil. Therefore, changes in B, v, N, or A will directly affect the rate of change of flux and consequently the induced e.m.f.