Class 12th Handwritten Physics Notes - Magnetic Effect of Currents
Class 12 CBSE Physics Chapter: Magnetic Effects of Current as per the latest CBSE syllabus: Magnetic Effects of Current 1. Introduction Electric current produces a magnetic field. This magnetic field can exert a force on magnets and other current-carrying conductors. 2. Oersted’s Experiment Observation : When current flows through a wire, it deflects a nearby magnetic compass needle. Conclusion : A current-carrying conductor produces a magnetic field around it. 3. Magnetic Field Due to a Current (a) Magnetic Field due to a Straight Current-Carrying Conductor The field lines are concentric circles centered on the wire. Direction : Given by the Right-Hand Thumb Rule . Magnitude at a distance r from a long straight wire: B = μ 0 I 2 π r B = \frac{\mu_0 I}{2\pi r} Where: μ 0 = 4 π × 10 − 7 T \cdotp m/A \mu_0 = 4\pi \times 10^{-7} \, \text{T·m/A} (permeability of free space) I I = current, r r = radial distance (b) Magnetic Field due to a ...