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Essential formulas: c = 1/sqrt(mu_0epsilon_0) = 3 x 10^8 m/s. I_d = epsilon_0d(Phi_E)/dt. E_0/B_0 = c. u = epsilon_0E^2 = B^2/mu_0 (u_E = u_B). I = (1/2)cepsilon_0E_0^2. S = (1/mu_0)(E x B). Pressure: I/c (absorb), 2I/c (reflect). v = c/n, n = sqrt(mu_repsilon_r). lambdaf = c.

JEE strategy by question type: (1) Displacement current: use I_d = epsilon_0AdE/dt or equivalently I_d = CdV/dt. (2) E-B relationship: B_0 = E_0/c (B is always much smaller numerically in SI). (3) Direction: use E x B for propagation direction. (4) Intensity: I = (1/2)cepsilon_0E_0^2 — memorize this one formula and derive the rest. (5) Radiation pressure: remember the factor of 2 for reflection. (6) Spectrum questions: know the order, sources, and one key application per region. (7) Speed in medium: v = c/n = c/sqrt(epsilon_r) for non-magnetic materials. Common traps: confusing absorption and reflection pressure, forgetting that E and B are in phase (not 90 degrees out of phase), and mixing up E_0 with E_rms.