Answer: E 0 /B 0 = c (speed of light).
- A E<sub>0</sub>/B<sub>0</sub> = c (speed of light)
- B E<sub>0</sub> = B<sub>0</sub>, with both fields numerically equal
- C E<sub>0</sub> = cB_0², with the magnetic amplitude squared
- D E<sub>0</sub>/B<sub>0</sub> = 1/c, the inverse of the actual relation
Correct answer: A. E<sub>0</sub>/B<sub>0</sub> = c (speed of light)
Explanation: For an EM wave: E<sub>0</sub>/B<sub>0</sub> = c. Since c = 3 × 10⁸ m/s, the magnetic field amplitude is much smaller (by factor c) than the electric field amplitude in SI units.
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.