Correct Answer:
A. Dielectric heating
Correct answer: Dielectric heating. Microwave ovens heat food primarily through dielectric (dipolar) heating, where polar water molecules rotate rapidly in response to an alternating high-frequency electromagnetic field (2.45 GHz).
Background: While older guidebooks loosely referenced resonance, dielectric heating is the standard scientific explanation.
- Reflection: Metal walls reflect microwaves to keep them contained inside the cavity.
- Refraction: Refraction is the bending of waves passing through different media.
- Damped oscillation: Refers to oscillations that decay in amplitude over time.
Did you know? Percy Spencer discovered microwave cooking in 1945 when a chocolate bar melted in his pocket near an active radar magnetron.
Memory trick: Microwave heating = Dielectric (dipolar water rotation) heating.