1. B due to a moving point charge where  0 = 4  x10 -7 T.m/A Biot-Savart law: B due to a current element B on the axis of a current loop B inside a solenoid B =  0 nI, where n =N/ B due to an infinite long straight wire Ampere’s Law: Note: Ampere’s law is valid only if currents are continuous with a high degree of symmetry We used Ampere’s law to determine magnetic fields for an infinite straight wire, a solenoid, and inside and outside a wire. Magnetic force on a current element

2. Right-hand rule: The magnetic lines of B curl around a current- carrying wire in the same direction as the fingers of the right-hand when the thumb points in the direction of the current as shown. Magnetic lines due to a current in circular coil. If you are standing to the left of the picture, the current in the coil is clockwise

3. Magnetic flux: In weber (Wb), 1Wb = 1 T.m 2 If a plane surface of area A and constant B with an angle  between directions of A and B If there are N turns Faraday’s Law: Lenz’s Law: The direction of the induced current is such that the induced field is to oppose the change in the original magnetic flux.

4. Inductance: Self-inductance: Self-inductance of a solenoid: Mutual inductance: Units of inductance: Henry (H) 1H = 1 Wb/A = 1 T.m 2 /A For example, the mutual inductance for The outer solenoid is

5. Magnetic energy stored in a inductor: Magnetic energy density: AC generator: emf generated: rms current: AC in a resistor: AC in an inductor: AC in a capacitor: Inductive reactance: X L =  LCapacitive reactance: X C = 1/  C Average power Dissipation: