May the Magnetic Force Be with You
Students become familiar with the cross product as related to magnetic fields.Copyright 2007 Oleg Alexandrov, Wikipedia Commons http://commons.wikimedia.org/wiki/Image:Right_hand_cross_product.png
After a demonstration of the deflection of an electron beam, students review their knowledge of the cross-product and the right-hand rule with example problems. Then they study the magnetic force on a charged particle, compared to the electric force. Provided lecture material covers the motion of a charged particle in a magnetic field with respect to the direction of the field. Finally, students apply these concepts to understand the magnetic force on a current carrying wire. Through the associated activity, students further explore the force on a current carrying wire.
In their designs, biomedical engineers carefully control the strong magnetic field of MRI machines in order to produce images that do not harm operating personnel or patients. The right-hand rule, commonly used in visualizing the cross product, can be used to study the direction of the magnetic force acting on a charged particle, such as a foreign body entering an MRI's magnetic field. In the Assessment section of this lesson, students use the right-hand rule to predict and test the direction of a magnetic force on a current carrying wire.
After this lesson, students should be able to:
- Use the cross product and force equation to determine in which direction a magnetic field acts on a moving particle.
- Describe the motion of a charged particle in a magnetic field.
- Calculate the force of a magnetic field on a current carrying wire.