TABLE OF CONTENTS Amp re's Force Law/Biot-Savart Law/Magnetic Induction/Magnetic Field Intensity/Amp re's Circuital Law/Magnetic Flux/Magnetic Dipole Moments/Torque on a Current Loop/Magnetic Vector and Scalar Potentials/Conditions at an Interface/Bound Currents and Magnetization/The Lorentz Force/Magnetic Circuits/Mutual Inductance/Internal Inductance/Magnetostatic Force
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| 3.1 According to Amp re's force law, the force d F 1 on a current element I 1 ds 1, interacting with another current element I 2 ds 2, shown in Fig. 3-1, is given by
Write an expression for the total force F 1 experienced by loop 1.  Figure 3-1 |
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| 3.2 Two infinitely long straight conductors, which are parallel to each other, are separated by a distance b. The conductors carry currents I 1 and I 2 in the directions shown in Fig. 3-2. Determine the mutual force per unit length of the conductors.  Figure 3-2 |
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| 3.3 Refer to Fig. 3-3. According to the Biot-Savart law, the magnetic flux density or magnetic induction d B at point P due to a current element I ds at Q is
where the tesla is denned by 1T = 1 N/A m. Rewrite ( 1) and ( 2) of Problem 3.1 for a current element and a current loop in an external field B 2.  Figure 3-3 |
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| 3.4 Express the B-field of a current loop if the origin of coordinates is chosen as in Fig. 3-4.  Figure 3-4 |
