Physics 223
30. Sources of the Magnetic Field 30.1 Biot-Savart Law 30.2 Force between two parallel wires 30.3 Ampere’s Law 30.4 Magnetic Field (B) of a Solenoid 30.5 Gauss’s Law in Magnetism
Biot-Savart Law B= μ 0 I / 4π ∫ (d s x r ̂ ) / r 2
Electric Currents Produce Magnetism I I B = μ 0 I / 2 a a
Electric Currents Produce Magnetism Right Hand Rule: Thumb points to B and curled fingers indicate I I I B
Electric Currents Produce Magnetism B = μ 0 I a 2 / 2( a 2 + x 2 ) 3/2 B x a
Electric Currents Produce Magnetism Right-Hand Rule: Thumb points to current ( I) and curled fingers indicate B I B B
Electric Currents Produce Magnetism Old wine … New bottle! I X
B of Infinitely-Long Wire I B B B = o I / 2 a
B of Finite-Length Wire I B B B = o I [sin θ 1 - sin θ 2 ] / 4 a
30.2 Force Between Two Currents F = o I 1 I 2 L / 2 a I1I1 I2I2
30.3 Ampere’s Law ∫B. ds = 0 I I B B
30.4 B of a Solenoid Application of Ampere’s Law ∫B. ds = 0 I B L = 0 N I B = 0 N I /L B = 0 n I L
30.5 Gauss’s Law in Magnetism ∫B. dA = B
Flux Through the Rectangular Loop B = 0 I b/2 ln(1 + a/c) I X c a b
That’s all folks!