Answer: Cause water molecules to vibrate (dielectric heating).
- A Cause water molecules to vibrate (dielectric heating)
- B Are strongly absorbed and reflected by metal cookware
- C Have wavelengths longer than AM radio broadcast waves
- D Cause ionization of atoms within the food, like X-rays
Correct answer: A. Cause water molecules to vibrate (dielectric heating)
Explanation: Microwave ovens use frequencies (~2.45 GHz) that efficiently couple to water molecules, causing them to rotate and vibrate, generating heat throughout the food uniformly.
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.