NapkinCalc

Physics 3 — Electricity & Magnetism

Making fields: the solenoid

continues from lesson 3 — values defined earlier in the course stay live here

Wrap wire into a coil and current makes a uniform field inside: B = μ₀·n·I. More turns per meter, more field — this is the electromagnet, the relay, the MRI bore:

μ0=4⋅π⋅10−7\mu_{0} = 4 \cdot \pi \cdot 10^{-7} = 1.2566×10−61.2566 \times 10^{-6} permeability of free space (T·m/A)
nturns=2000n_{turns} = 2000 turns per meter
Icoil=5I_{coil} = 5 current (A)
Bsol=μ0⋅nturns⋅IcoilB_{sol} = \mu_{0} \cdot n_{turns} \cdot I_{coil} = 0.01260.0126 field inside (T)