1. §5.2: Biot-Savart Law Christopher Crawford PHY 417 2015-01-21

2. Outline Magnetic force law Magnetic field & Lorentz Force – force on two straight wires Force between current elements – analog of Coulomb’s law Separation of field – Lorentz force & Biot-Savart law Examples Straight wire Circular loop Current sheet 2

3. Magnetic field & Lorentz force Magnetic field definition from torque – electrostatic analogy Magnetic field from force on a straight wire – current element Lorentz force for currents – TWO right hand rules – parity ? Lorentz force for moving particles – or ANY current element Relativistic version 3

4. Biot-Savart Law Coulomb’s Law Biot-Savart Law Consistency of separation of force into: I’dl’ –> B –> I dl 4

5. Example 5.5: straight wire Similar to Ch. 2: line charge 5

6. Example 5.6: dipole loop Closest thing to an electric point charge 6

7. Example: current sheet 7