Misconception 1: "Displacement current is displacement of charges"

Reality: The word "displacement" here refers to Maxwell's term for the electric displacement field D = ε_{0}E. Displacement current Id = ε_{0}(dΦ_E/dt) has nothing to do with mechanical displacement of charges. It is a mathematical term that represents the effect of a time-varying electric field.

Misconception 2: "Higher frequency EM waves travel faster in vacuum"

Reality: Speed in vacuum c = 1/$\sqrt{μ_{0}ε_{0}}$ is a universal constant — independent of frequency, wavelength, polarisation, or amplitude. A gamma photon and a radio photon emitted simultaneously travel side by side and arrive simultaneously.

Misconception 3: "EM waves need ether (a medium) to propagate"

Reality: The 19th century hypothesis of "ether" was disproved by the Michelson-Morley experiment. EM waves are self-sustaining field oscillations that propagate through complete vacuum. No medium is needed — they carry their own "substance" (the fields themselves).

Misconception 4: "E and B are perpendicular in direction AND phase"

Reality: E ⊥ B only refers to their SPATIAL directions (they point along perpendicular axes). Their TEMPORAL variation is completely in phase — both E and B reach maximum together, zero together, and minimum together at any given point. The misunderstanding conflates spatial and temporal relationships.

Misconception 5: "X-rays from a hospital machine are 'stronger' gamma rays"

Reality: X-rays and gamma rays are distinguished by SOURCE, not by energy or frequency. Hospital X-ray machines use the Coolidge tube (electron deceleration). Gamma rays come from radioactive nuclei. They can have the same frequency yet be classified differently. The "strength" (penetrating power) depends on energy, not the X/gamma label.

Misconception 6: "Visible light carries more energy than radio waves, so it's more intense"

Reality: Individual photon energy E = hf is higher for visible than radio waves. But intensity (W/$m^{2}$) depends on BOTH photon energy AND number of photons per unit area per unit time. A powerful radio transmitter can deliver more intensity than dim visible light.

Misconception 7: "Microwaves ionise food"

Reality: Ionising radiation = UV, X-rays, gamma rays (high enough frequency to knock electrons from atoms). Microwaves are non-ionising — they only cause molecular rotation. This is why microwave ovens are generally considered safe (unlike X-ray machines).