describe how a microwave oven works (EM waves + thermal physics)

microwaves are Electromagnetic waves with a wavelength in the order of 10^-6m (the prefix for 10^-6 is micro, just as 10^-3 is milli). these short wavelength waves have a high energy due to equation E=hc/λ, showing that energy is inversely proportional to wavelength. The high energy waves incident on the food source, cause molecules on the surface to vibrate. This is due to the exchange of energy, where the energy of the photon has transferred to kinetic energy of the food molecule (mostly water H20 molecules). These surface molecules will then collide with their neighbour molecules, transferring kinetic vibrational energy to their neighbours. This process, known as conduction, disperses kinetic energy throughout the food source. Kinetic energy of a group of many molecules in a system is the definition of thermal energy. therefore, as more microwaves interact with the food, it gains more kinetic energy, and thus gains more thermal energy - the food heats up.  

AE

Related Physics A Level answers

All answers ▸

The energy of a photon is 1.5MeV. Calculate the frequency associated with this photon energy and state an appropriate unit in your answer.


How do I solve a problem about a mass on a slide?


Find the angle at which total internal refraction takes place when light is going from glass to air.


A yacht is sailing through water that is flowing due west at 2m/s. The velocity of the yacht relative to the water is 6m/s due south. The yacht has a resultant velocity of V m/s on a bearing of theta. Find V and theta