How to Calculate Magnetic Force
What is Magnetic Force?
The magnetic force on a moving charge is given by the Lorentz force law: F = qvB sinθ. This force is always perpendicular to both the velocity and the magnetic field, causing charged particles to move in circular or helical paths. The Lorentz force is the working principle behind particle accelerators, mass spectrometers, electric motors, and MRI machines.
Formula
- F
- |q| × v × B × sin(θ) — |q| × v × B × sin(θ)
- B
- magnetic field (tesla) — magnetic field (tesla)
Step-by-Step Guide
- 1F = |q| × v × B × sin(θ)
- 2q = charge (coulombs), v = velocity (m/s), B = magnetic field (tesla)
- 3θ = angle between velocity vector and B field
- 4Maximum force when θ = 90° (perpendicular to field)
- 5Zero force when θ = 0° (parallel to field — charge moves along field lines)
Worked Examples
Frequently Asked Questions
What is Magnetic Force?
The magnetic force on a moving charge is given by the Lorentz force law: F = qvB sinθ. This force is always perpendicular to both the velocity and the magnetic field, causing charged particles to move in circular or helical paths
How accurate is the Magnetic Force calculator?
The calculator uses the standard published formula for magnetic force. Results are accurate to the precision of the inputs you provide. For financial, medical, or legal decisions, always verify with a qualified professional.
What units does the Magnetic Force calculator use?
This calculator works with inches. You can enter values in the units shown — the calculator handles all conversions internally.
What formula does the Magnetic Force calculator use?
The core formula is: F = |q| × v × B × sin(θ). Each step in the calculation is shown so you can verify the result manually.
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