# magneticField() Creates and returns a field behavior that interacts with charged items. ``` class func magneticField() -> Self ``` ## Return Value A field behavior object that applies a magnetic field to charged items. ## Discussion The magnetic field behavior models a uniform magnetic field in the positive-z direction—that is, coming out of the screen. The amount of force applied by the field is modeled after the second part of the Lorentz equation (`F = qvB`). When the velocity of a charged item is perpendicular to the uniform magnetic field, the item feels a force normal to both the velocity and the field, resulting in a counter-clockwise rotation. Specifying a negative value for the [`strength`](/documentation/UIKit/UIFieldBehavior/strength) of the field results in a clockwise rotation. You can use magnetic fields as a way to apply forces to an object that are based on charge instead of mass. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)