Microwaves are used in a microwave oven because their frequency
Correct answer: A. is absorbed strongly by water molecules, which then rotate and heat the food
- A. is absorbed strongly by water molecules, which then rotate and heat the food
- B. ionises the food
- C. reflects off water
- D. changes the chemical composition of the food
Explanation
The oscillating field makes polar water molecules flip back and forth, and the friction between them heats the food from within rather than only at the surface. Microwaves are non ionising, since their photon energy is far too low to remove electrons, so they do not make food radioactive. Metal containers are unsuitable because they reflect the waves and can cause arcing.
Report an error
The more specific you are, the faster it gets fixed. A source beats an opinion.
Prefer email? support@testustad.com
About Electromagnetic Waves
Electromagnetic waves consist of mutually perpendicular, oscillating electric and magnetic fields that also remain perpendicular to the direction of propagation. They travel through vacuum at the speed of light and include radio waves, microwaves, infrared, visible, ultraviolet, X-rays and gamma rays. Unlike mechanical waves, they do not require a material medium.
Practise Alternating Current
592 free Alternating Current MCQs from Physics, each with the correct answer and an explanation. Unlimited attempts, no account needed.
Discussion
Stuck on an option, or know a faster way to get there? Ask or explain it here.
No comments yet. Be the first to explain this one.
Exams that ask Physics questions like this
Physics is on 16 papers prepared for on TestUstad, and all of them draw the same bank, so this question is worth knowing for every one of them.
More Electromagnetic Waves questions
The speed of all electromagnetic waves in a vacuum is
Which of the following electromagnetic waves has the longest wavelength?
Electromagnetic waves consist of
Ultraviolet radiation is more damaging to skin than visible light because ultraviolet photons
The wave that has the highest frequency and penetrating power is
Modern system of navigation satellites called ___________?