Answer: The square of the amplitude (E 0 ² or B 0 ²).
- A The square of the amplitude (E<sub>0</sub>² or B<sub>0</sub>²)
- B The amplitude E<sub>0</sub> raised to the first power only
- C The frequency of oscillation of the wave
- D The wavelength of the propagating wave
Correct answer: A. The square of the amplitude (E<sub>0</sub>² or B<sub>0</sub>²)
Explanation: Intensity I = average power/area. For an EM wave, I ∝ E<sub>0</sub>² (or B<sub>0</sub>²). Doubling the amplitude quadruples the intensity.
In an electromagnetic wave, the oscillating electric field (E) and magnetic field (B) are perpendicular to each other and to the direction the wave travels - a purely transverse wave that needs no medium, unlike sound.
Concept context
Maxwell's equations, EM spectrum, properties, and applications of each band.