Magnetic Force on Wire Calculator

Magnetic Force on a Current-Carrying Wire

When electric current flows through a wire placed in a magnetic field, each moving charge experiences the Lorentz force. For a straight wire, the net magnetic force is given by the cross product of current direction and magnetic field direction.

Formula

$$F = BIL\sin\alpha$$

Here $B$ is magnetic flux density (tesla), $I$ is current (amperes), $L$ is wire length (meters), and $\alpha$ is the angle between the current direction and the magnetic field. Maximum force occurs when current and field are perpendicular ($\alpha = 90°$); force is zero when they are parallel.

Practical Notes

This is the Ampere force used in electric motors, loudspeakers, and magnetic levitation demonstrations. A wire hanging freely in a strong field will move when current is switched on. Use consistent SI units for accurate results.

Frequently Asked Questions

Why does the angle matter?

Only the component of current perpendicular to the magnetic field contributes to force. The sine factor accounts for this geometry.

What units should I use?

Use teslas for $B$, amperes for $I$, and meters for $L$. The result is in newtons.

When is force zero?

When current and magnetic field are parallel ($\alpha = 0°$) or when any of $B$, $I$, or $L$ is zero.

Is this the same as the Lorentz force?

Yes. For a straight wire, the Lorentz force on all moving charges sums to $F = BIL\sin\alpha$.

Does wire orientation affect the result?

Yes. Enter the angle between the current direction and the magnetic field. Perpendicular alignment gives maximum force.

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Magnetic Force on Current Wire Calculator

Magnetic Force on a Current-Carrying Wire

Formula

Practical Notes

Frequently Asked Questions

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