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#coil coupling

3 public questions tagged with this topic.

In a system of two coils, the mutual inductance depends on which property of the setup?

**Lenz's law** induced current direction opposes change in flux causing it, e = -N dΦ/dt negative sign, conservation of energy. Magnet moved towards coil south pole first, approaching south pole increasing flux into coil with south polarity, coil face nearest magnet becomes south pole to repel, opposing approach, so face becomes south pole, repelling magnet. Mutual inductance depends on the geometry (e.g., coil sizes, separation, orientation) and the medium’s permeability, affecting how much flux from one coil links with the other. Using Φ = B A cosθ, e = -N dΦ/dt = -N A dB/dt = B l v = N B A

Ref: NCERT > Physics Book > Electromagnetic Induction > Lenz's Law, Eddy Currents and Applications

A solenoid of 550 turns and length 1.1 m induces an emf of 1.65 V in a nearby coil when its current changes from 0 to 3

**Mutual inductance calculation** M = e₂/(dI₁/dt), for 200 turns length 0.5 m nearby coil e=0.5 V dI=2 A dt=0.2 s dI/dt=10 A/s, M=0.5/10=0.05 H, depends on geometry, orientation, number of turns, area, separation, coupling coefficient k = M/√(L₁ L₂) ≤1. ε = M (Δ I/Δ t) . Δ I = 3 - 0 = 3 A , Δ t = 0.3 s . M = (ε/(Δ I/Δ t)) = (1.65/(3/0.3)) = (1.65/10) = 0.165 H . Using Φ = B A cosθ, e = -N dΦ/dt = -N A dB/dt = B l v = N B A ω sinωt, L = μ₀ N²A/l, M

Ref: NCERT > Physics Book > Electromagnetic Induction > Mutual Induction and Mutual Inductance

A solenoid of 300 turns and length 0.6 m induces an emf of 0.9 V in a nearby coil when its current changes from 1 A to 3

**Mutual inductance calculation** M = e₂/(dI₁/dt), for 200 turns length 0.5 m nearby coil e=0.5 V dI=2 A dt=0.2 s dI/dt=10 A/s, M=0.5/10=0.05 H, depends on geometry, orientation, number of turns, area, separation, coupling coefficient k = M/√(L₁ L₂) ≤1. ε = M (Δ I/Δ t) . Δ I = 3 - 1 = 2 A , Δ t = 0.3 s . M = (ε/(Δ I/Δ t)) = (0.9/(2/0.3)) = (0.9/6.67) ≈ 0.135 H . Using Φ = B A cosθ, e = -N dΦ/dt = -N A dB/dt = B l v = N B A ω sinωt, L = μ₀ N²A/l, M

Ref: NCERT > Physics Book > Electromagnetic Induction > Mutual Induction and Mutual Inductance