Question

why are microwaves, but not radio waves nor ultraviolet (uv) waves, used to heat up food?
electromagnetic waves carry energy in unique, fixed amounts called quanta (singular:
quantum). the amount of energy in one quantum depends upon the frequency of the wave.
matter, like water and fat molecules in food, absorb and emit specific quanta of energy. since
microwaves, radio waves, and uv waves have specific wavelengths and frequencies, they
interact differently with matter.
complete the sentences.
a microwave has a frequency and carries energy than a uv wave.
but the quanta of energy carried by a causes water and fat molecules to
vibrate and produce heat when absorbed. so, rather than
, are used to heat food.

Explanation:

Step1: Recall the relationship between frequency and energy

The energy of an electromagnetic wave is directly proportional to its frequency ($E = h
u$, where $h$ is Planck's constant and $
u$ is frequency). UV waves have a higher frequency than microwaves. So, a microwave has a lower frequency and carries less energy than a UV wave.

Step2: Consider the interaction with matter

Microwaves have quanta of energy that match the energy required to make water and fat molecules vibrate. Radio - wave quanta have too little energy (low frequency) to cause significant vibration for heating, while UV quanta have too much energy (high frequency) and can cause chemical changes (like in sunburn, not just heating) rather than just heating through molecular vibration. So, the quanta of energy carried by a microwave causes water and fat molecules to vibrate and produce heat when absorbed. So microwaves, rather than radio waves or UV waves, are used to heat food.

Answer:

A microwave has a lower frequency and carries less energy than a UV wave. But the quanta of energy carried by a microwave causes water and fat molecules to vibrate and produce heat when absorbed. So microwaves, rather than radio waves or UV waves, are used to heat food.