: Determined by the Right-Hand Thumb Rule . If you hold the wire with your thumb pointing in the direction of the current, your curled fingers indicate the direction of the magnetic field lines. 3. Applications of Biot-Savart Law
∮B⋅dl=μ0Ienclosedcontour integral of bold cap B center dot d bold l equals mu sub 0 cap I sub enclosed end-sub : Determined by the Right-Hand Thumb Rule
The Biot-Savart Law is used to find the magnetic field at a point due to a small current element ( Idlcap I d l it experiences a force:
B=μ0I2πrcap B equals the fraction with numerator mu sub 0 cap I and denominator 2 pi r end-fraction : Determined by the Right-Hand Thumb Rule
: A solenoid bent into a circle (doughnut shape). The field inside is 5. Force on a Moving Charge (Lorentz Force) When a charge moves with velocity in a magnetic field , it experiences a force: