Question
The condition under which a microwave oven heats up a food item containing water molecules most efficiently is
A.
the frequency of the microwave must match the resonant frequency of the water molecules
B.
the frequency of the microwave has no relation with natural frequency of water molecules
C.
microwave are heat waves, so always produce heating
D.
infra-red waves produce heating in a microwave oven
Answer :
the frequency of the microwave must match the resonant frequency of the water molecules
Solution :
It is an electromagnetic wave. The frequency of the microwave oven must match the resonant frequency of the water molecules.
NOTE
In the presence of microwaves, water molecules oscillate with frequency of microwaves and large heat is developed.