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 🌈 Chapter 8: Electromagnetic Waves – Class 12 Physics --- 🔹 Introduction Electromagnetic waves are transverse waves consisting of electric field (E) and magnetic field (B) oscillating perpendicular to each other and the direction of wave propagation. Proposed by James Clerk Maxwell. --- 🔹 Displacement Current Maxwell added the concept of displacement current to Ampere’s law. I_d = \varepsilon_0 \frac{d\Phi_E}{dt} Where:  = Displacement current  = Permittivity of free space  = Rate of change of electric flux 📌 Diagram: Parallel plate capacitor showing conduction and displacement current --- 🔹 Maxwell’s Equations (Conceptually) 1. Gauss’s law for electricity 2. Gauss’s law for magnetism 3. Faraday’s law of induction 4. Ampere-Maxwell law --- 🔹 Nature of Electromagnetic Waves Electric and Magnetic fields oscillate perpendicular to each other and to the direction of propagation. They do not require any medium to travel. Speed of EM Waves (in vacuum): c = \frac{1}{...

 ⚡️ Chapter 7 – Alternating Current (AC) – Class 12 Physics --- 🔹 What is Alternating Current? Alternating Current (AC): An electric current that changes its magnitude and direction with time. Represented as: I(t) = I_0 \sin(\omega t)  = Peak current  = Angular frequency  --- 🔹 AC vs DC Property Alternating Current (AC) Direct Current (DC) Direction Changes with time Constant Source Generator Battery Transmission Less loss More loss --- 🔹 Peak, RMS, and Average Value 1. Peak Value (I₀, V₀): Maximum value of current or voltage. 2. Root Mean Square (RMS) Value: I_{\text{rms}} = \frac{I_0}{\sqrt{2}}, \quad V_{\text{rms}} = \frac{V_0}{\sqrt{2}} 📌 Important Diagram: Graph of AC waveform showing I vs t --- 🔹 AC through Resistor (R) Voltage and current are in the same phase. 📌 Diagram: Phasor diagram for AC through R --- 🔹 AC through Inductor (L) Current lags voltage by . Inductive reactance: X_L = \omega L 📌 Diagram: Phasor diagram for AC through L --- 🔹 AC throug...