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Solenoid Magnetic Field Equation:
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The solenoid magnetic field equation calculates the magnetic field strength (B) inside a long solenoid based on the current through it, number of turns, and length of the solenoid. This assumes the solenoid is much longer than its diameter.
The calculator uses the solenoid equation:
Where:
Explanation: The equation shows that the magnetic field is directly proportional to the current and number of turns, and inversely proportional to the solenoid length.
Details: Calculating solenoid magnetic fields is essential for designing electromagnets, electric motors, transformers, and other electromagnetic devices.
Tips: Enter current in amperes, number of turns (must be ≥1), and length in meters (must be >0). All values must be positive numbers.
Q1: What is the permeability of free space (μ₀)?
A: It's a physical constant equal to 4π × 10⁻⁷ H/m that represents how much resistance the vacuum of space offers to the formation of a magnetic field.
Q2: Does this equation work for short solenoids?
A: The equation is most accurate for long solenoids (length ≫ diameter). For short solenoids, more complex calculations are needed.
Q3: What are typical magnetic field strengths?
A: Earth's field is ~50 μT, refrigerator magnets ~5 mT, MRI machines 1.5-3 T, and strong lab magnets up to 20 T.
Q4: How does core material affect the field?
A: Inserting a ferromagnetic core (like iron) can multiply the field by the material's relative permeability (μᵣ), which can be hundreds or thousands.
Q5: What's the difference between B and H fields?
A: B is magnetic flux density (measured in Tesla), while H is magnetic field strength (A/m). They're related by B = μH, where μ is permeability.