P12 Electromagnetic waves Flashcards
Are electromagnetic (EM) waves longitudinal or transverse waves?
transverse
Explain why EM waves are not mechanical waves.
they can travel through a vacuum (don’t need a substance to travel through)
What do EM waves transfer from their source to an absorber?
energy
List the different types of waves in the EM spectrum in order of decreasing wavelength (increasing frequency).
radio, microwave, infrared, visible, ultraviolet, X-rays, gamma
Which part of the EM spectrum can humans see?
visible light
How can electromagnetic waves be produced?
changes inside an atom/atomic nucleus
How are gamma rays produced?
changes in the nucleus of an atom, for example during radioactive decay
How can radio waves be produced?
oscillations in an electrical circuit
How can we detect radio waves?
waves are absorbed and create an alternating current with the same frequency as the radio wave
What are radio waves used for?
transmitting television, mobile phone, and Bluetooth signals
What are microwaves used for?
satellite communications, cooking food
What is infrared radiation used for?
heating, remote controls, infrared cameras, cooking food
Which types of EM waves are harmful to the human body?
ultraviolet, X-rays, gamma rays
What are the hazards of being exposed to ultraviolet radiation?
damage skin cells, sunburn, increase risk of skin cancer, age skin prematurely, blindness
Why are X-rays used for medical imaging?
they pass through flesh but not bone
